Road dust, not cars, Kolkata’s worst polluter: TERI study
Times of India | 10 November 2025
Kolkata: The biggest source of the city's air pollution is road dust, a recently released report has revealed, upending the popular perception that vehicles and factories are the worst offenders.
The source-apportionment study, commissioned by West Bengal Pollution Control Board and conducted by TERI in Kolkata and Howrah in the 2024-25 financial year, found that resuspension of road dust is the biggest contributor to Kolkata's air pollution both during summer and winter. Resuspension refers to lifting of dust settled on the road surface back into the air by wind or vehicle movement.
The study says that road dust accounts for around 35% of PM10 and 16% of PM2.5 — the two worst pollutants that enter the lungs and cause a host of critical ailments — in the city's ambient air throughout the year.
In comparison, vehicles contribute 10-12% of PM10 and 15-18% of PM2.5, while industry accounts for 14-16% of PM10 and 17% of PM2.5 around the year.
Emissions from residential areas rise sharply in winter — from 6% during summer to 11% for PM10 and from 9% to 18% for PM2.5 — mainly because of increased biomass burning. Transboundary pollution (mainly in Bangladesh) adds to Kolkata's air pollution burden, with the study showing that it contributes about 13% of the ultrafine particulate matter during summer and around 2% during winter.Turn
The study did not consider the impact of pollution in neighbouring states on the city's air. A preliminary study by IIT Delhi had showed that states in the Indo-Gangetic plain were responsible for as much as 55% of Kolkata's PM2.5 during winter.
The TERI study found that the Kolkata Municipal Corporation (KMC) area accounts for the lion's share of the city's pollution — 47% of PM10 and 40% of PM2.5 during summer, and 44% of PM10 and 33% of PM2.5 during winter.
The Howrah Municipal Corporation (HMC) area contributes just 2% of PM10 and 1% of PM2.5 during summer, while its winter impact is more pronounced — 3% for PM10 and 15% for PM2.5. Pollutants blowing in from areas not covered by the study make up a massive chunk of the city's air pollution load — 37% of PM10 in summer and 30% in winter. For PM2.5, the figures are 46% during summer and 43% in winter.
The state pollution control board and TERI explained how the city's weather plays a big role in determining the volume of pollutants.
Strong and warm winds in summer push up dust and smoke, keeping the air pollution relatively low. The situation flips during winter. Weak and cold winds undergo little upward movement, keeping the pollutants trapped closer to the ground. "That is why the city's air quality dips to ‘poor' and ‘very poor' every winter," said PCB chairman Kalyan Rudra.
The study highlights the need for urgent measures to control dust and smoke. rather than focusing solely on vehicle and factory emissions, according to PCB scientists The PCB and the Centre have advised the city authorities to prioritise key actions such as end-to-end paving of roads, keeping the road surface free of potholes and modernising crematoriums and setting up more charging stations for e-vehicles.