CHENNAI: Chennai may have made progress in its fight against air pollution, as per an analysis by environmental think tank EnviroCatalysts. The report states that the city’s annual average PM2.5 levels have dropped from 49 µg/m3 in 2017, the baseline year for the National Clean Air Programme (NCAP), to 28 µg/m3 in 2024, marking a 43% improvement in air quality. However, insufficient monitoring stations and data gaps continue to raise concerns.
Ideally, a city of Chennai’s size should have 30 continuous ambient air quality monitoring stations (CAAQMS). However, it currently has only nine. Only seven of these nine stations had data for the full year of 2024. The remaining two in Ennore and Manali, both industrial regions, didn’t have data for nine and seven months respectively.
The analysis also reveals uneven progress across Chennai’s neighbourhoods. Alandur Bus Depot reported the highest annual PM2.5 concentration at 45 µg/m3, while Kodungaiyur recorded the lowest at 13 µg/m3. Four stations reported concentrations at or below 25 µg/m3, meeting India’s National Ambient Air Quality Standards (NAAQS), which set the annual PM2.5 limit at 40 µg/m3.
With this, however, Chennai has achieved the NCAP’s set goal of reducing pollution levels by 40% by 2024. Experts believe the city must now target WHO’s interim standard of 15 µg/m3 and eventually strive for the guideline value of 5 µg/m3 to ensure healthier air for its residents.
Sunil Dahiya, founder of EnviroCatalysts, said, “No doubt Chennai has made some progress, but these numbers do not represent the entire city since the number of CAAQMS are less compared to other metro cities. But given the challenges posed by industrial emissions, vehicular pollution, and high levels of fuel combustion, these results are remarkable, and being a coastal city helps as pollutants get dispersed quickly.” Dahiya pointed out that cities like Delhi, which struggle with annual PM2.5 levels nearing 100 µg/m3, can learn from Chennai’s efforts.
He added that better progress could be achieved through stricter industrial emission standards, modernisation of public transportation, and a transition away from fossil fuels in the energy and transport sectors. These measures could help Chennai meet WHO’s interim and long-term air quality targets.
Prabhakaran Veerarasu of Poovulagin Nanbargal, however, warned against removing Chennai from the NCAP list, arguing that doing so could disrupt the flow of resources critical for further improvement, such as air quality monitoring infrastructure and pollution control initiatives.
Prabhakaran said the government must continue financing air quality management programmes and expand the network of monitoring stations to ensure comprehensive and accurate data collection. He highlighted Chennai’s unique opportunity to become the first Indian city to meet WHO air quality guidelines by 2030, given its geographical advantages and current progress.