TNPCB data on Deepavali underplays real extent of air pollution, says environmental group

Environmental organisation Poovulagin Nanbargal has called for a review of how air pollution is measured in Tamil Nadu, alleging the current methods understate the real impact of firecracker emissions during Deepavali.

According to the Tamil Nadu Pollution Control Board (TNPCB), Chennai’s Air Quality Index (AQI) between 6 a.m. on October 20 and 6 a.m. on October 21 ranged from 190 to 332. However, Poovulagin Nanbargal said the actual pollution levels were far higher, as private monitoring apps showed readings of up to 993 AQI in parts of the city on Deepavali night.

The group criticised the TNPCB’s use of 24-hour averages, saying this conceals the intensity of pollution during peak hours when the air becomes dangerously toxic. “In areas like Valasaravakkam, where the 24-hour average was 332 AQI, the real-time level between 8 p.m. and 11 p.m. could have exceeded 800 AQI,” the organisation said in a statement.

It also pointed out that the TNPCB monitors cannot record levels above 500 AQI, making it impossible to know how bad air quality truly gets. It urged the government to release hourly data, increase real-time monitoring stations in cities, and remove the 500-AQI ceiling.

Poovulagin Nanbargal further demanded stricter time restrictions on bursting crackers, a complete ban in hill stations such as Ooty and Kodaikanal, and a pollution tax on fireworks based on the “polluter pays” principle. It also called for a long-term plan to provide alternative livelihoods for firecracker workers.