Smaller cities in Bihar and Rajasthan emerged as pollution hotspots, rivalling major metropolitan areas like Delhi
Photo for representation: iStock As winter settled in, the resurgence of toxic air pollution once again cast a shadow over public health, starting notably earlier than usual and exacerbated by meteorological factors such as low rainfall in September-October and sluggish winds throughout the season.
Delhi-based think tank Centre for Science and Environment’s comprehensive review of winter air quality has brought to light alarming trends. Delhi and Chandigarh were the most polluted Union territories / states in the country, recording PM2.5 levels of 188 microgram per cubic metre and 100.9 µg / m³, respectively. Conversely, Karnataka emerged as a beacon of cleaner air with a winter average of 32 µg / m³.
The conclusive report for the 2023-24 winter season revealed a stark reality: North and East India remained the most polluted regions, with North India experiencing a significant deterioration in air quality compared to the previous winter, while East India showed signs of improvement. South India maintained its top position with the lowest PM2.5 levels.
Digging deeper into city-level analysis, smaller cities in Bihar and Rajasthan emerged as pollution hotspots, rivalling major metropolitan areas like Delhi. Cities like Begusarai in Bihar and Hanumangarh in Rajasthan are on par with the pollution levels seen in the national capital, with average winter PM2.5 levels of 213.5 µg / m³ and 171.6 µg / m³, respectively. Furthermore, industrial towns in South India and the Himalayan region were also found to be grappling with high pollution levels.
Conversely, cities like Gangtok in Sikkim and Silchar in Assam shone with cleaner air quality, with average PM2.5 levels of 9.8 µg / m³ and 14.9 µg / m³, respectively.
The average PM2.5 levels across the country’s major regions reaffirmed the severity of the situation, with North and East India bearing the brunt of pollution. The North recorded an average of 89.9 µg / m³ PM2.5, while the East followed closely at 85.9 µg / m³. Notably, the National Capital Region (NCR) surpassed these levels, averaging 113.6 µg / m³.
Diwali and its aftermath marked a period of exceptionally poor air quality nationwide, with daily average PM2.5 levels peaking at 120 µg / m³ after the festival. NCR deviated from this trend, experiencing its peak 10 days before Diwali, attributed to factors like crop stubble burning and restrictions on firecrackers during the festival.
The regional peaks in pollution levels underline the gravity of the situation, with North India reaching a 24-hour average of 156.7 µg / m³ and NCR hitting 218.4 µg / m³ on November 3, 2023, exceeding the peak of 202 µg / m³ on Diwali day.
Regional winter average PM2.5 levels & winter peak of 2023-24
Winter is defined as the period from October 1, 2023 to January 31, 2024. Source: CSE analysis of CPCB’s real-time air quality data
Compared to the previous winter, this season saw a 13 per cent increase in PM2.5 levels in northeastern cities and an 8 per cent increase in northern cities. NCR cities saw a 14 per centrise, while eastern cities witnessed a 29 per centdecline.
Cities in the west and south of the country experienced a 10 per centpollution reduction, with central Indian cities showing minimal change. Overall, the country saw an 8 per centreduction in winter pollution levels compared to the previous year.
As we reflect on the findings of the comprehensive winter air quality review, it’s clear that urgent measures are needed to address India’s air pollution crisis. The disparities in air quality across regions highlight the complexity of the challenge.
Spatial variation in winter PM2.5 levels across India 2023-24
Source: CSE analysis of CPCB’s real-time air quality data
Considering the impact of meteorological factors, regional peaks, and seasonal fluctuations, it becomes evident that no region is immune to this omnipresent problem. Poor air puts the health and well-being of millions at risk and thus, experts urge policymakers, industries and individuals to come together and implement sustainable solutions.
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