Pintu Saha, who has driven an auto rickshaw on Kolkata's roads for over thirty years, is currently battling a severe lung condition attributed to prolonged exposure to dense traffic pollution. He is unaware of the recent remarks made by West Bengal's chief minister regarding measures to combat the city's air pollution.
Mamata Banerjee, the chief minister, has recently applauded her administration on social media for its efforts in reducing Kolkata's air pollution, which earned praise from the union environment ministry. However, Kolkata continues to be the second most polluted metropolitan area in the country, following Delhi.
Transport-related pollution, along with biomass burning, is a leading cause of Kolkata's poor air quality compared to the national standard, which international reports attribute to high mortality and morbidity rates among the city's inhabitants. Notably, Kolkata experiences the highest exposure to vehicular air pollution among major cities in the country, as a significant portion of its residents live near major roads.
The exponential increase in the number of vehicles in the city has not helped. According to union government statistics, the city's annual registration of 4-wheelers has surged more than five times since 2016, reaching 31,991 in 2024 from 6,202 in 2016. Meanwhile, the registration of 2-wheelers has more than doubled, rising from 39,029 in 2016 to 90,871 in 2024.
A recent research conducted by Bose Institute, a national scientific organisation based in Kolkata, revealed that PM 2.5 levels, a significant pollutant capable of penetrating deep into the lungs and causing various diseases, surpassed 70 microgrammes 75 per cent of the time during winter, despite the city investing around Rs 750 crore since 2019 as part of the National Clean Air Programme (NCAP). The national threshold is 60 microgrammes.
Even during summer and pre-monsoon, PM2.5 levels stayed above 70 microgrammes for 25-35 per cent of the time.
“Kolkata again shows the way! Govt of India has awarded majorly three cities including Kolkata for significant reduction in Particulate Matter (PM )10 level and improved the overall Air Quality Index (AQI),” wrote Banerjee on X (formerly Twitter) on May 16, 2025.
Kolkata was awarded the third-highest performance-based incentive in the country by the Union Ministry of Environment, Forest and Climate Change for improving improvement in ambient air quality.
The Kolkata Urban Agglomeration that includes the Kolkata Municipal Corporation alongside the fringe areas has been recognised as one of India’s best-performing cities under NCAP, based on a performance assessment of 48 major Indian cities carried out by the Central Pollution Control Board (CPCB). This showed that Kolkata registered a 2.2 per cent reduction in PM10 concentration from 2022-23 to 2023-24; while the number of good air quality days also increased.
However, the overall pollution status is hardly encouraging. CPCB data showed that during 2023-24, Kolkata’s PM10 level was 94 microgramme, a slight slide from 97 microgrammes a year ago, but still more than 50 per cent higher than the national annual limit of 60 microgrammes. The level is second after Delhi among metro cities.
Other studies also corroborate the trend. The World Air Quality Report by IQAir indicated that Kolkata had the second highest average AQI in 2024, with a reading of 45.6, following Delhi, which recorded 108.3. Experts and activists argued that the deterioration in air quality can be attributed to inadequate public transport improvements and the dominance of private sector transport, including auto-rickshaws and app-based commercial vehicles. They claimed both policy and implementation are to blame.
“In our youth, we used to regularly avail public transport like trams and buses to go to the school and colleges. But now trams are as good as dead in city, while public buses are few and far between. Metro, whose route has been extended recently, is a welcome addition. But most people are now forced to use autos and totos (electric three-wheelers) and app-based commercial vehicles, those who can afford,” pointed out Raghu Jana, a transport activist.
Jana, who is a cycle crusader, complained that the government is also not encouraging the environment-friendly cycles as a transport option, while it is a critical component of urban mobility all over the world in this era of climate change.
“It is really bizarre why the government is hell-bent to wind up trams in city, the oldest mass transport mode in Kolkata, while it has been a key component in the transport mix of most global cities and while they are going big on electrical vehicles,” stated Mahadeb Shee, who has long been fighting for the cause of trams and even moved court with the cause of tram revival.
Subhas Datta, an environmental activist known for pushing legal action against vehicular pollution in the city, claimed that the state government is strategically backing efforts to reintroduce 15-year-old commercial vehicles, which were previously banned by the Kolkata High Court due to environmental concerns, instead of promoting pollution-free public transportation.
“The bus owners' association has recently petitioned to high court demanding the withdrawal of its earlier order scrapping all the 15 years old commercial vehicles on pollution ground; and clearly the state government is providing the tactical support behind the move. Already the city has almost turned into an old age home for public transport; the latest move may turn out to be a death knell for city transport,” alleged Datta. Datta and other activists complained that the city’ public transport is at the brink of breaking down.
The data also corroborates the decline of public transport in city. In 2016, 666 new public service vehicles were registered in Kolkata. Since then, unlike private vehicles, the number either remained constant or plummeted over the years, before showing some upward movement in 2024, with 993 new additions, though the overall picture remained dismal.
“With government not accepting our long-time demand to increase the bus fare, we have no option but to ultimately shut down our business,” said Abasesh Daw, from minibus owners’ association.
Ultrafine PM 2.5 was responsible for over 185,000 premature deaths in Kolkata during 2011-19, said the report by US research organisation Health Effects Institute. According to the report Air Quality and Health in Cities, Kolkata is fourth in terms of deaths triggered by PM2.5 — 185,390 — within the most populous cities during 2011-19.
"Data from the Health Effects Institute (HEI) report show that residents of Kolkata are exposed to poor air quality, including very high levels of PM2.5. It is critical to address air pollution in the city, and plan for targeted actions on sources including transportation, industries and waste,” said Pallavi Pant, a senior scientist of HEI, had told DTE earlier.
"Kolkata, with high PM2.5 exposure, needs the stringently operated time-bound multi-sector action to meet the clean air target,” stated Anumita Roy Choudhury, an air pollution expert with Delhi-based think tank Centre for Science and Environment.
Kolkata is suffering substantially from both tail-pipe and non-tail-pipe emission modes, said pulmonologist Arup Haldar from the Calcutta Medical Research Institute. “A recent survey carried out by us in West Bengal and Jharkhand, the result of which got published in the Journal of Association of Chest Physicians in 2024, showed that 56 per cent of the respondents suffered from sneezing, while 44 per cent suffered from cough,” said Haldar. “We found exposure to traffic-related air pollution was a major cause behind the trend and Kolkata suffers more exposure compared to others.”