Slow murder continues: Black Deposits that cannot be removed

Air pollution was the second largest killer globally after blood pressure, recording a dubious tally of 8.1 million deaths in 2021. Of this, a staggering 2.6 million deaths occurred in South Asia alone. To this is added debilitating chronic diseases and a range of ill health. With a population over 1 billion, India recorded 2.1 million deaths, including 237,000 ozone-pollution related deaths. The bigger shocker was the deeply worrying tally of more than 700,000 deaths among children under five years, making air pollution the second leading risk factor after malnutrition globally. As many as 500,000 of these child deaths were linked to household air pollution from cooking indoors using dirty fuels in Africa and Asia. More than 260,600 of these child deaths were yet again reported in South Asia. The air pollution-linked death rate in children under the age of five in South Asia was 164 deaths per 100,000 in contrast to the global average of 108 deaths per 100,000. This death tally remained high despite the 53 per cent drop in death rate since 2000, due to growing access to clean energy for cooking, improved healthcare, nutrition and awareness. Polluted air is a big trigger for pneumonia and other respiratory infections and allergic diseases in children.

These grim results were from the ‘State of Global Air 2024’ (SOGA), a collaborative assessment by the US-based Health Effects Institute (HEI) and Institute for Health Metrics and Evaluation’s Global Burden of Disease (GBD) project. These results were linked to the disease burden estimated for 2021 in about 200 countries. ‘This new report offers a stark reminder of the significant impacts air pollution has on human health, with far too much of the burden borne by young children, older populations, and low- and middle-income countries,’ said Pallavi Pant, HEI’s Head of Global Health who oversaw the SOGA report.

While the spotlight of this annual tracker of health impact of air pollution continues to be on PM2.5 (fine particulate matter with a diameter of 2.5 μm or less) and ozone, nitrogen dioxide (NO2) were also added in this risk assessment for the first time. Even though PM2.5 (both ambient and household) accounts for more than 90 per cent of the total air pollution disease burden, NO2 and ozone are the growing risk factors globally. The new spotlight on the exposure to NO2 brings out the importance of the growing risk from traffic exhaust in densely populated urban areas. This is a leading risk factor for the development of childhood asthma. About 55 per cent of 194 countries studied did not yet meet the annual World Health Organization’s (WHO’s) Air Quality Guidelines of 10 μg/m3, resulting in 42 per cent of the world’s population being exposed to unacceptable levels. The report pointed out that in contrast to PM2.5, seven of the 10 countries with the highest NO2 exposures were high-income countries in West Asia (including Bahrain, Qatar, Kuwait, Lebanon, and the United Arab Emirates). Russia and Turkey also experienced high NO2 levels. The highest exposures to NO2 had been noted in countries with high socio-development index, including Singapore, Japan and Canada.

In 2021, exposure to NO2 was linked to 177,000 healthy years of life lost for children and adolescents. There is a strong connection between long-term exposure to traffic-related air pollution and early death due to cardiovascular diseases and lung cancer, asthma onset in children and adults, and acute lower-respiratory-tract infections in children. NO2 is also a catalyst for formation of ozone, yet another very harmful gas. NO2 reacts with other chemicals in the atmosphere to produce both particulate matter and ozone. According to the SOGA report, nearly 490,000 deaths were linked to ozone, and countries in West Asia (Qatar, Bahrain, Kuwait, Saudi Arabia, and Iraq), South Asia (Nepal, India, Bangladesh, and Pakistan), and East Asia (Republic of Korea) reported the highest average ozone exposures in 2020.

Ozone levels have also increased in South Asia. In 2021, ozone was responsible for 56 per cent of all global ozone deaths reported in the region. The report further notes that the US, partly due to its sizable population, widespread ozone pollution and relatively high rates of Chronic Obstructive Pulmonary Disease (COPD), saw 14,000 deaths in 2021, higher than any other high-income country. Since 2010, the overall number of ozone-linked COPD deaths has risen by nearly 20 per cent. This is expected to increase as the population gets older.

While South Asia, including India, continues to bear the biggest brunt of particulate pollution-related health impacts, the proportion of population experiencing high ozone exposures is also increasing in India, Nigeria, Pakistan, and Brazil. These countries have noted increases of more than 10 per cent in ambient ozone exposures in the last decade. With populations of over 1 billion each, India and China had recorded 2.1 million and 2.3 million deaths respectively, and together accounted for nearly 55 per cent of the total global disease burden from particulate matter. In 2021, nearly 50 per cent of all ozone-related COPD deaths were in India, followed by China and Bangladesh.

The SOGA report highlighted what is called ‘the climate penalty’. It noted that the chemical reactions that form ozone increase when the air is warmer, especially during heatwaves. Evidence showed that ozone, also a greenhouse gas, spiked during heatwaves in China and Europe. Exposure to ozone is associated with an increased risk of both acute and chronic respiratory illnesses like COPD. Ozone also impacts plants, crops and vegetation. Ozone can reduce crop yields, damage biodiversity and undermine food security and nutrition. Climate change can exacerbate the health burden of non-communicable diseases, including heart and lung diseases, during heatwaves.

In India, there is an insidious link between outdoor and household air pollution. The 2015 report of the Steering Committee on Air Pollution and Health under the Union Ministry of Health and Family Welfare estimated that household air pollution could contribute up to 25-30 per cent of outdoor air pollution in India. Several epidemiological studies are available in the country on the effect of household air pollution. The first ever ‘mother-child’ cohort study was carried out by Kalpana Balakrishnan and her team from Sri Ramachandra Medical College, Chennai. They followed the cohort over time to investigate the link between exposure to PM2.5 during pregnancy and low birthweight in an integrated rural-urban setting. This showed that a 10 μg/m3 increase in exposure to PM2.5 during pregnancy could decrease birthweight by 4 g, lead to a 2 per cent increase in the prevalence of low birthweight and cause 70 g decrease in birthweight in households using solid fuels. However, according to a global study ‘Global, regional, and national burden of ambient and household PM2.5-related neonatal disorders, 1990-2019’, published in March 2023, the global neonatal disorders burden attributable to household PM2.5 decreased by 38.35 per cent in the past 30 years. This is mainly due to the decrease in the household PM2.5-related neonatal disorders burden, which dropped by 52.33 per cent during the period, according to the study published in Ecotoxicology and Environmental Safety. According to the ‘State of Global Air 2019’ report of IHME, India had reduced its proportion of households cooking with solid fuels from 76 per cent in 2005 to 60 per cent in 2017 due to improved access to liquefied petroleum gas. Yet solid fuel use remained high among the lower income groups. This still accounted for about two-thirds of the PM2.5-related neonatal disease burden.

Air pollution caused more than 100,000 premature deaths in some of India’s largest cities in 2005-18, according to a research published in Science Advances on April 8, 2022. Bengaluru (93.9), Hyderabad (96.4), Kolkata (82.1) and Pune (73.6) recorded the highest number of such deaths per 100,000 population, respectively, during this period. Mumbai saw 65.5 premature deaths per 100,000 populations, Surat 58.4, Chennai 48 and Ahmedabad 47.7. ‘We wanted to evaluate fast-growing cities in the tropics, which are projected to transform into megacities by 2100, and eight of these cities are in India,’ said Karn Vohra, lead author of the research paper and research fellow from the University College London. The team wanted to quantify long-term changes in air quality in cities which lack extensive surface monitoring networks. Vohra and his colleagues relied on instruments aboard the US National Aeronautics and Space Administration (NASA) and the European Space Agency satellites to gather data on air pollutants in the tropical regions between 2005 and 2018. Vohra said, ‘The tropics are the next frontier in air pollution. They are experiencing population growth at an unprecedented pace. Also, most countries in the tropics are yet to implement policies and set up infrastructure to mitigate air pollution.’ Their analysis observed significant yearly increases in pollutants worldwide. In tropical cities, nitrogen dioxide (NO2) concentration in the atmosphere rose up to 14 per cent and that of fine particles (PM2.5) rose 8 per cent, the report shows. In 2005, Kolkata had recorded 39,200 premature deaths, Ahmedabad 10,500, Surat 5,800, Mumbai 30,400, Pune 7,400, Bengaluru 9,500, Chennai 11,200 and Hyderabad 9,900, the team observed. In 2018, the figures rose to 54,000 for Kolkata, 18,400 for Ahmedabad, 15,000 for Surat, 48,300 for Mumbai, 15,500 for Pune, 21,000 for Bengaluru, 20,800 for Chennai and 23,700 for Hyderabad. Overall, India had 123,900 premature deaths from long-term exposure to PM2.5 in 2005, which increased to 223,200 in 2018.

Indians are indeed losing on life expectancy due to foul air. Worsening air pollution is robbing a decade of the life expectancy of those living in Delhi, the capital city regarded as the world’s most polluted, according to an analysis by the University of Chicago published in 2022. Indians, on average, are losing about five years. The Energy Policy Institute at the University of Chicago (EPIC)’s Air Quality Life Index (AQLI), in its India factsheet released in July 2022, noted that these figures were ‘relative to what (the life expectancy) would be if the World Health Organization (WHO) guideline regarding fine particulate pollution (PM2.5) of 5 microgram per cubic metre (μg/m3) was met.’ In comparison, 1.8 years of life are lost due to child and maternal malnutrition, while smoking robs nearly two years of life expectancy in India. The report noted that the country’s entire population—all 1.4 billion—breathes air with particulate pollution level well above the WHO guideline. Also, more than 63 per cent breathe air worse than the national air quality standard of 40 μg/m3. Nearly 40 per cent of India’s population residing in IGP—which includes Bihar, Chandigarh, Delhi, Haryana, Punjab, Uttar Pradesh and West Bengal—were set to lose some 7.6 years of life expectancy. Those in Lucknow will lose 9.5 years if current pollution levels persist, the report says. Uttar Pradesh, Bihar, Haryana and Tripura had the most years to gain—8.2 years, 7.9 years, 7.4 years and 6 years respectively—if pollution levels met the WHO standard, according to the report. ‘Since 1998, average annual particulate pollution has increased by 61.4 per cent, leading to a further reduction in average life expectancy of 2.1 years. Since 2013, about 44 per cent of the world’s increase in pollution has come from India,’ the report notes.

A plethora of local and global evidence, thus, builds the case for urgent action to control air pollution. Despite the mounting evidence, people often do not understand how air pollution triggers health conditions that lead to death and illness. This was evident when nine-year-old Ella Kissi Debrah died due to an acute asthma attack in south London in 2013 and her mother moved the court challenging that air pollution was responsible for her child’s death. The incident ultimately led to the landmark judgement and coroner’s report in 2020 that made Ella the first person in the world to have air pollution cited as a cause of death. Kalpana Balakrishnan of Sri Ramachandra Medical College, Chennai, pointed out, ‘Gaps in evidence never close in science. There is already enough evidence on exposures to rest the case. Also remember, absence of evidence is not the evidence of absence.’ And in India we witness that every moment: slow murder by breathing toxic air.

On November 3, 2023 as night descended over Delhi, hundreds of children, coughing and gasping, thronged the out-patient department and emergency ward of Chacha Nehru Bal Chikitsalaya. Soon, the super specialty paediatric government hospital in east Delhi ran out of nebulisers and beds. Doctors at the hospital had been dreading the prospect since the last week of October, when the average air quality in the national capital remained in ‘very poor’ category for six consecutive days before plummeting to ‘severe’ category on November 3, with AQI value reaching a staggering/hazardous 468. AQI values over 100 are considered unhealthy. Doctors in the national capital and in adjoining areas are familiar with this seasonal plague. As the region chokes on dust and smoke in winter every year, hospitals receive an exceptionally large number of patients with respiratory problems. Ajay Shukla, director and medical superintendent of Atal Bihari Vajpayee Institute of Medical Sciences and Dr Ram Manohar Lohia (ABVIMS-RML) Hospital, one of the country’s premier hospitals run by the Union government, said the hospital records a 30 per cent rise in respiratory-related illnesses during severe pollution days. But this episode of pollution was overwhelming, even though expected.

On November 6, 2023, ABVIMS-RML opened a dedicated weekly Pollution Out-Patient Department, a first-of-its-kind in the country, to cater to patients suffering from the impact of unhealthy air. Shukla said the initiative was to ensure that all the pollution-related cases—from cough to eye infection to headache—could be seen by doctors of different departments at one place. In Vallabhbhai Patel Chest Institute (VPCI), another prominent hospital in north Delhi, hospital staff shared worrying data: between November 2 and November 10, 2023, the hospital on average received 50 new cases of respiratory illnesses on a daily basis. What’s perturbing was that most patients visiting the hospitals with respiratory ailments were under 14 years. Ambavasan A, a senior resident doctor at the emergency ward of ABVIMS-RML, said the hospital was flooded with children with respiratory problems, and their number and severity of the condition varied as per the pollution level. Medha Mittal, endocrinologist at Chacha Nehru Bal Chikitsalaya, said, ‘Delhi’s air pollution is resulting in a rapid increase in respiratory illnesses among children.’

There are reasons children are more vulnerable to air pollution than adults. Since the respiratory system is not completely developed in children, particularly in newborns and infants, they breathe faster than adults to ensure adequate provision of oxygen into the blood. Children also have high metabolic rate—the rate at which they use up energy—and therefore have a higher oxygen demand, which in turn results in higher respiratory rate than adults. Studies estimate that children typically breathe 40 times in a minute, which is more than double the respiratory rate of adults. ‘As they breathe more air per body size and have smaller airways than adults, they are at an increased risk of developing respiratory diseases and exacerbation of asthma,’ stated a study by researchers from Germany and the Czech Republic, published in Urban Climate on June 4, 2022. Of the many air pollutants that children breathe, the dreaded one is the fine inhalable PM2.5 that originates from different local combustion sources such as vehicles, industries and burning of waste, and is laced with toxins. Since the particulate matter is smaller than the red blood cells, studies have established that it can go deep into the lungs, escape to the bloodstream and also breach the blood-brain barrier, with hundreds of known and unknown health effects. The German and Czech Republic researchers examined the potential differences of PM2.5 exposure between children and adults in an urban area and found that the concentration of PM2.5 decreased with increasing height above ground. Since the breathing levels of children are closer to pollutants emitted near ground, it makes them more vulnerable to emissions by traffic-related exhausts and whirled up fine particles.

Arvind Kumar, chairperson of Institute for Chest Surgery-Chest Onco Surgery and Lung Transplantation, Medanta, Gurugram, and founder of Lung Care Foundation, shared a few photographs of lungs with Down To Earth magazine to show the impact of air pollution on respiratory health of those living in areas with poor air quality. ‘Healthy lungs look absolutely pink. However, we regularly see black deposits in the lungs of most non-smoker adults and children up to 14 years of age who come to us with respiratory illnesses. These black deposits cannot be removed and eventually damage the lungs,’ said Kumar, adding that children are inhaling more toxic air than adults.

The impact of air pollution on children’s health begins even before they are conceived. It starts by impairing the fertility of both men and women. Research shows that exposure to air pollution affected ovarian reserve in women. A study conducted on women in China showed that the level of anti-müllerian hormone—a predictor of ovarian reserve—changed by -8.8 per cent, -2.1 per cent, -1.9 per cent and -4.5 per cent per 10 μg/m3 increase in PM1, PM2.5, PM10 and NO2. ‘Theoretically, PM with smaller size and larger surface area volume ratio, e.g. PM with diameter ≤1 μm (PM1), is more likely to penetrate through the alveolar capillary barrier and then impact directly the ovarian function via blood circulation,’ noted the paper published in Environmental Research on February 1, 2023. Though the underlying mechanism of female fertility decline caused by air pollutants remains unclear, limited evidence speculates that oxidative stress and inflammatory response caused by air pollution may be one crucial pathway, the researchers say. Similarly, a study in China on 33,876 men shows that exposure to PM2.5 and PM10 decrease total and progressive sperm motility. The findings were published in jama Networks on February 17, 2022.

If the child is conceived against all odds, air pollution can hinder their development in the uterus as pollutants can cross the placenta into the baby’s blood. In a study published in the Journal of Family and Reproductive Health in June 2017, the researchers from Iran found an inverse relationship between the exposure to air pollution in the first trimester of pregnancy and the weight of placenta, which sustained the development of the foetus. A comprehensive review of studies, published in The Lancet Planetary Health, reported the presence of black carbon particles in cord blood which enter foetal liver, lungs and brain. The presence of the pollutants continued to harm the growing foetus so much that it tended to increase the risk of preterm birth. This, in turn, could increase the chances of stillbirth, low birthweight, underdeveloped lungs in the baby, and death of the baby during or shortly after birth. Sudhir Gupta, former chairperson of the department of gynaecology at Baba Raghav Das (BRD) Medical College, Gorakhpur, Uttar Pradesh, explained how air pollution affects the development of foetus, ‘Due to pollution, pregnant women cannot get enough oxygen from the ambient air, which affects the natural development of the foetus. Furthermore, the higher the sulphur contents in the air, the greater the risk of miscarriage,’ he said. Bhupendra Sharma, chairperson of the paediatrics department of BRD Medical College, said, ‘Air pollution can also lead to anaemia in expectant mothers, which greatly reduces the chance of delivering a healthy baby.’

Even if the child survives the onslaught of pollutants in utero, multiple studies show that the exposure before and after birth could impair their neurodevelopment skills, such as intellectual functioning, memory and learning, attention and executive functions, verbal language, numerical ability and motor and/or sensor motor functions. ‘The pollutants that seem to represent the greatest risk are PM2.5, NO2 and PAHS [polycyclic aromatic hydrocarbons],’ states a review of 30 research papers, published in Neuroscience & Behavioral Reviews in May 2022. Just like in adults, the child’s blood pressure is known to shoot up due to exposure to air pollution during pregnancy—higher the mean PM2.5 and black carbon exposure during the third trimester, higher the newborn’s systolic blood pressure. Exposure to air pollution in utero can also lead to congenital heart defects in children, making survival difficult. Lungs, too, are not spared from the onslaught. It has been observed that higher the exposure to air pollution during infancy, lower the lung capacity. Acute respiratory infections too seem to affect children who are more exposed to PM2.5. A survey of under-five children indicated that 10 μg/m3 increase in PM2.5 was associated with greater chances of contracting an infection.

Gut health too gets affected—pollutants inhaled during the first six months of life adversely affect the composition of gut microbes which could increase risk of allergies, obesity and diabetes, and even affect brain development. A 2020 study published in Gut Microbes stated that these microbes and their by-products shaped appetite, insulin sensitivity, immunity, mood and cognition, and a poor mix of microbes could leave the child prone to asthma, type 2 diabetes and other chronic illnesses. Exposure to air pollution in the womb can also change the protein activity of the baby. For example, pollutants have been found to affect cell processes such as autophagy, ‘self-eating’ of damaged cells that usually occur in response to stress, according to a study presented at the European Respiratory Society International Congress in Milan, Italy, on September 12, 2023. Exposure to higher NO2 was linked to decreased levels of sirtuin1 (SIRT1), a protein that plays a protective role in stress resistance, inflammation and ageing. Evidence is also mounting around the impact of pollution sources on health. Studies in Europe have investigated the impact of vehicular emissions on child health and impact on neuron development along the highways. In 2013, a study found correlation between early exposure to traffic pollution and several childhood cancers.

And as if to complete the circle of destruction, exposure to air pollution also impacts the reproductive health of adolescent girls. Higher exposure to particulate matter in utero and throughout childhood has been implicated in the early onset of menarche because these particles seem to have endocrine-disrupting properties.

Health experts in India are already generating evidence to implicate air pollution in the high mortality and poor health of children in the country. In November 2023, the Collaboration for Air Pollution and Health Effect Research, India (CAPHER India), a national research network focused on air pollution and health effects steered by All India Institute Of Medical Sciences Delhi (AIIMS), New Delhi, and the Indian Institute of Technology (IIT), Delhi, released a policy brief, which said that air pollution was the third leading risk factor for deaths in under-five children in the country. For children under 14 years, it was the second leading risk factor for deaths. Since 2010, Delhi, Punjab and Haryana had seen the highest percentage of deaths in under-five children related to outdoor PM2.5 exposures, according to the policy brief which had reviewed key Indian studies on the issue.

One of the studies published in April 2022 in Science of the Total Environment provided evidence that PM2.5 impacts infant mortality primarily through neonatal mortality. Another study points towards a link between air pollution and stunting. The study by Germany’s Heidelberg University and France’s University of Rennes, published in the Journal of Environmental Economics and Management in May 2022, estimated that the percentages of stunted and severely stunted children in India would drop by 10.4 and 5.17 percentage points, respectively, if average pollution levels were reduced to who-recommended levels. A large-scale study by the Population Council, New Delhi, and the International Development Department, University of Birmingham, UK, published in the journal BMJ Global Health in July 2020, confirmed that exposure to PM10 not only affected children but also pregnant women resulting in premature birth. This indicated that the probability of newborn mortality increased by 6 per cent for every 10-unit increase in PM10 levels.

Another study found a significant correlation between the chemical components of PM2.5 and low birthweight, anaemia and acute respiratory infections in children aged below five years. The study, ‘Cumulative effect of PM2.5 components is larger than the effect of PM2.5 mass on child health in India’, published in Nature on October 31, 2023, showed that for every 10μg/m3 increase in PM2.5 exposure, the prevalence of anaemia, acute respiratory infection and low birthweight increased by 10 per cent, 11 per cent and 5 per cent among children under five in India. PM2.5 is a mixture of various components with different sources and toxicities. The study showed the cumulative effect of PM2.5 components—ammonia (NO3-), fine ammonium (NH4+), elemental carbon (EC) and organic carbon (OC)—to be larger than the effect of PM2.5 mass on child health in India. Another Delhi-based study, published in April 2022, also established a link between acute exposure to PM2.5 chemical species and mortality during winters. ‘There might be differences in the methods of studies and study design, including time series, cross-sectional, exposure based health outcomes and many more. However, an interesting fact is that in both these studies NO3 showed the highest impact,’ said Ekta Chowdhary, researcher and author of the Nature study.

Yet another area of investigation is childhood cancer. While there is enough evidence to show that exposure to air pollution can lead to cancer in adults, it is not studied adequately in children. There is some indication. Studies have identified air pollutants such as benzene, NOx and particulate matter as culprits in childhood Non-Hodgkins Lymphoma, a type of cancer that begins in the lymphatic system which is part of the body’s immune system. A study published in January 2023 in Nature found an association between exposure to PM2.5 level and risk of acute lymphoblastic leukaemia among children, which is a cancer of blood and bone marrow. But this correlation is not studied adequately in India.

The latest available data by the National Cancer Registry Programme is only from 2012 to 2016. But it showed a pattern. The proportion of childhood cancers relative to cancers in all age groups in different cities varied between 0.7 per cent and 3.7 per cent. Delhi was the worst affected among places with a cancer registry—the country had 28 Population Based Cancer Registries between these years. Here, as many as 203.1 boys per million were affected by all the broad kinds of cancers compared to just 12.2 per million in Pasighat in Arunachal Pradesh. Patiala’s cancer registry reported 121.2 cases per million boys. Mumbai, which too is facing a pollution challenge, stood at 10th place. In case of girls in the age group of 0-14, the number was 125.4 per million in Delhi compared to 12.1 in East Khasi Hills District. Patiala stood at 9th position with 74 cases per million. The data from India’s National Cancer Registry Programme showed that Delhi was badly affected by leukaemia too—as many as 84.2 boys per million, between the ages of 0-14 are affected compared to just 7.3 per million in Meghalaya. For girls, this number stood at 47.2 cases per million, the second-highest after Imphal West district in Manipur, compared to just 4.9 per million in Cachar district of Assam. In case of lymphomas, the number stood at 30.7 per million for boys in Delhi, much lower than the 2.3 per million cases seen in Meghalaya. For girls, Delhi had the third highest cases of lymphomas which stood at 10 per million. The report also showed that among the Asian countries studied for boys, Delhi had the highest cases per million followed by China’s Jianmeng. In case of girls, Delhi had the sixth highest number of cases. For all countries included in the study, Delhi had the 6th highest number of cancer cases for boys and 10th highest in case of girls.

A person living in the sprawling IGP, spread across northern India (as well as eastern Pakistan, southern Nepal and most of Bangladesh), will live seven years less than people in other parts of the country. That means if a resident of the states and Union Territories of Bihar, Chandigarh, Delhi, Haryana, Punjab, Uttar Pradesh and West Bengal, will on average have a shorter life than their counterparts in the rest of country, as per a 2019 study by University of Chicago’s EPIC.

There are various reasons for this. Smoke from crop fires is one of the main reasons, but not the only one. As per NASA, influxes of dust from the Thar Desert to the west, motor vehicle emissions, industrial and construction activity, fireworks, and fires for heating and cooking also produce particulate matter and other pollutants. ‘Geography and weather can exacerbate the region’s poor air quality. Temperature inversions are common in November and December as cold air rolls off the Tibetan Plateau and mixes with smoky air from the Indo-Gangetic Plain. An inversion can function like a lid, with warm air trapping pollutants near the surface. The low-hanging haze becomes hemmed in between the Himalayas to the north and the Vindhya Range to the south,’ according to NASA. And that is not good news for those who live in this region. IGP is home to 9 per cent of the global population. India occupies most of the region, and 40 per cent of its population lives on the plain. Air pollution in the region has soared 72 per cent from 1998 to 2016, as per the University of Chicago study, and did not meet the WHO guideline for fine particulate pollution.

Doctors point to a steep rise in respiratory illnesses among children across the Indo-Gangetic region, where air quality remains in the “poor” category almost throughout the year. Air quality analysis by Pune-based climate technology firm Respirer Living Sciences Pvt Ltd showed that the Indo-Gangetic region had seven of the 10 most polluted cities in the country. In 2018, non-profit Climate Agenda studied 14 districts of Uttar Pradesh and found that small cities like Gorakhpur and Mau were more polluted than the national capital Delhi and state capital Lucknow. Air pollution plagues rural areas as well and the entire state of Uttar Pradesh is under a ‘health emergency’, stated the non-profit’s report, ‘Air Kills’. An analysis of Bihar’s air quality in the winter season, from October 2022 to February 2023, by Centre for Science and Environment (CSE) showed that the PM2.5 levels in at least 10 towns in the state were substantially worse than that of Delhi.

This is alarming. According to the Census of India, 2011, the Indo-Gangetic states—Punjab, Haryana, National Capital Territory of Delhi, Uttar Pradesh, West Bengal, Assam and Bihar—are home to almost half of the children (in the age group of 0-14 years) in the country and two-thirds of under-five children who are most vulnerable to air pollution. Mohan P George, scientist with CSE, said, ‘In the Indo-Gangetic region, a month-old infant with a weight of 4 kg and breathing 40 cycles a minute will inhale 184 μg of PM2.5 a day.’ George’s calculation was based on the annual average of 100 μg of PM2.5 level in the region’s air. The impact is palpable. At a national conference, organised by the Indian Academy of Paediatrics in Kolkata in November 2023, pulmonologists point out that one in every two children in the metropolitan city suffered from respiratory disorders triggered by air pollution. ‘I treat children in northern fringe of city and can safely vouch that the number of patients has increased several times in the past few decades, though the actual impact, both long- and short-term, is difficult to be spelt out due to inadequate data,’ said Subhamoy Mukherjee, a paediatrician practising in Kolkata for more than three decades.

Arup Halder, another pulmonologist in Kolkata, said that first-generation asthma patients among children are on the rise. ‘Earlier, asthma patients usually had a family history of the condition, but now a sizable number of children seem to be developing asthma because of exposure to air pollution. The problem increases especially in the winter when the air quality worsens,’ said Halder. In Bihar, there have been widespread reports of children suffering from respiratory infections, breathlessness and allergies, particularly during the winter months when the air quality hits the lowest points. Athar Ansari, professor, paediatric department at Nalanda Medical College and Hospital, a state government-run hospital in Patna, said that roughly a third of children and even some infants coming to the hospital suffered from difficulty in breathing. ‘Manifestation of allergies is increasing among children due to air pollution,’ said Ansari. Jayant Prakash, head of paediatrics department at Indira Gandhi Institute of Medical Sciences, Patna, said, ‘We have come across cases where newborns do not cry immediately after delivery and have difficulty breathing due to shortage of oxygen in their hyperactive airways because of pollution.’

The way that wind disperses pollution is a determining factor in the overall air quality management in regions. This not only needs to look at the local sources of pollution but also the pollution brought to the area from outside sources by wind. The downwind areas will be more impacted by the major pollution sources in upwind areas. Pollutants can travel long distances making it tougher for the downwind states to meet the clean air standards. Already, evidence suggests that a city like Delhi receives nearly 60 per cent of its pollution from outside the city, while Delhi itself contributes about 40 per cent of the winter particulate pollution in downwind Noida, Uttar Pradesh. This phenomenon has become a major concern in the IGP area due to its unique meteorology, landlocked ecosystem and high pollution and population. The National Green Tribunal in its directive dated September 9, 2021, took cognisance of the high particulate pollution in IGP compared to other regions and sought advanced air pollution abatement measures.

This led to an integrated assessment of IGP and a regional emissions inventory by the expert committee under the Central Pollution Control Board. It highlighted that Uttar Pradesh was the highest PM2.5 emitter in the region followed by West Bengal, Bihar, Punjab and Haryana. The industry sector alone accounted for 48.5 per cent of the total emissions in the region. Solid fuels for household cooking contributed as much as 19 per cent with highest contribution from Uttar Pradesh, Bihar and West Bengal. Affordable cooking energy sources remain a challenge. The main contributors to transport pollution are the metropolitan cities like Delhi, Kolkata, Lucknow and the industrial areas.

It is challenging for any city or town in IGP to meet the clean air targets if the regional cleanup is not achieved. The framework for a formal adoption of integrated management of airshed is not yet in place. This requires an aligned and coordinated action across the airshed that may have several administrative and political overlaps. This will require an operative framework and state council. Such a precedent has now been set in Delhi and the National Capital Region (NCR). Public movement, judicial intervention and the subsequent setting up of the Air Commission for the Delhi-NCR and beyond has established the principle of regional integrated planning for four states in NCR. This needs to be leveraged to create a framework for all other regions. Globally, national governments have begun to develop such a framework for management of transboundary pollution within the country and between countries.

‘Air pollution is the biggest public health challenge,’ said Maria Neira, head of WHO’s work on climate, environment and health. During the 28th Conference of Parties (COP28) to the UN Framework Convention on Climate Change (UNFCCC held in Dubai in November-December 2023, as many as 123 countries signed a new declaration on climate and health to recognise the linkage between climate change and public health. The COP28 Presidency and who together issued the ‘COP28 UAE Declaration on Climate and Health’, which aimed to accelerate action to protect public health and communities from the growing climate impacts and strengthen healthcare systems to cope with the effects of extreme heat, air pollution, infectious and zoonotic diseases and environmental risk factors. The declaration stated that devastating health impacts were already evident from the almost 9 million annual deaths from air pollution and exposure of 189 million people to extreme weather events annually. This indicated that the protection of health had to become central to climate action. This new declaration sought policy intervention to build more climate-resilient health systems, cross-sectoral collaboration to reduce emissions, maximise the health benefits of climate action and increase finance for climate and health solutions. Signatories also committed to incorporate health targets in their national climate plans and improve international collaboration to address the health risks of climate change and monitor progress in all global forums including future COPS and health ministerial. The significant aspect of this initiative is the effort made to get commitments on finance. Collectively, a wide range of partners and stakeholders committed to dedicate US $1 billion to meet the growing needs of the climate-health crisis.

Efforts to integrate climate action with health protection started way back in 2016. That is when WHO along with the Government of France, which then held the COP presidency, had jointly hosted the second global conference on health and climate to build healthier societies through implementation of the Paris Agreement. There was a plea to use the Paris climate treaty also as a public health treaty. WHO had warned that, as per the ‘Global Burden of Disease’ study, 23 per cent of the global deaths were linked to the environment including air pollution that was worsened by climate change. Moreover, climate change was likely to kill an additional 250,000 or more people each year by 2030. Most of these deaths would occur due to climatic stress, food insecurity and vector-borne diseases. Deaths and devastation from extreme weather events would magnify the health burden several times in the developing world and would erode economic gains especially in low income countries and island nations. The spotlight was on air pollution that kills around 9 million globally and is also a climate rogue.

If health is integrated with climate action, it can help target opportunities for mitigation and adaptation across sectors, promote integrated health mitigation strategies, strengthen core public health systems and scale up more aligned decarbonisation action. More evidence based action on health risks and benefits can support decision making. Global governance can work more effectively for the larger public good and well-being. This can not only facilitate the global finance flow but also influence national budgets and action to address the high health costs from climate change. Clearly, health can be a powerful lever to mainstream equity across multi-sector solutions.

The UN Environment Programme (UNEP) has already convened the Climate and Clean Air Coalition with support from other global agencies and multilateral bodies that have membership of a large number of countries for joint action on short-lived climate pollutants (SLCPs). WHO has further underscored the importance of this linkage and action. This effort requires a more effective interface with the UNFCCC process for comprehensive mitigation measures to maximise air quality, public health and welfare gains while fast-tracking CO2 reduction and building climate resilience.

Countries are already shaping their clean air and climate programmes, policies and implementation strategies to meet clean air targets. Interlinking the learning from these programmes at local and global level and strategic support can have a multiplier effect. A growing number of countries have started to include air pollution in their reporting on nationally determined commitments (NDC) to UNFCCC, and plan to revise NDCs in 2025. This needs to include assessment of public-health benefits and low-carbon gains. Countries that are reporting on clean air action to capture the learning curve and promote cross learning must be engaged and convened.

Several global platforms and forums have been established alongside the COP process for more advanced action in several sectoral areas, including clean energy transition, clean cooking, and zero emissions vehicle (ZEV) transition that can be leveraged to accelerate SLCP action in different regions. Some of these platforms include the Declaration on 100 per cent transition to zero emissions by 2030-40, the ZEV Transition Council, which represents 50 per cent of the global car market and Solar Alliance.

Global and national networks should be convened to sensitise them about SLCPs and the linkage between clean air and climate action and cross learning should be promoted. This can support local action in the Global South with science, good data and best practice approaches. There is considerable opportunity in the early stages of motorisation and industrialisation to be preventive and avoid pollution-intensive pathways. Engagement to influence global climate finance mechanisms must be built and additional finance including bilateral and multilateral funding need to be unlocked and mainstreamed with appropriate indicators to assess the co-benefit outcomes from the investments.

Campaigns to improve public visibility of these issues must be designed and public and policy understanding of science, policy and action related to SLCPs deepened to help build the new narrative. This requires creative communication on good practices and innovations, to influence opinion and mobilise opinion makers and local stakeholders in different regions. Building a global database and inventory of greenhouse gases and SLCP sources and emissions must be enabled and local institutional capability be strengthened to inform action.

This was first published as part of Slow Murder Continues: India’s suffocating journey of knowing and forgetting the deadly air pollution (2025), by the Centre for Science and Environment. It documents 40 years of reportage on air pollution and the fight against it in India. Download it here