Toxic cocktail of pollution during early winter in Delhi-NCR

December 01, 2025

Anumita Roychowdhury and Sharanjeet Kaur
Lead analysis: Sharanjeet Kaur
Centre for Science and Environment, New Delhi, December 1, 2025

The new assessment of the early winter trends (October-November) and annual air quality trends in Delhi by the Centre for Science and Environment (CSE), exposes the growing toxicity of the air, stubborn and elevated trends during early winter, worsening of air quality in smaller towns of the National Capital region (NCR), and the risk of reversal of long term air quality gains in the city.

“Delhi and NCR cannot hide behind the smokescreen of farm fires any more as even with much lesser contribution to local air quality this time, air quality has turned very poor to severe exposing the imapct of local sources. But more worrying is the daily synchronised rise of PM2.5 and other toxic gases of nitrogen dioxide (NO2) and carbon monoxide (CO) largely from vehicles and combustion sources, creating a toxic cocktail that has gone unnoticed. The longer term air quality trend in Delhi has also plateaeued without showing improvement. This signals urgent need for deep rooted shifts in infrastructure and systems to upscale action to cut emissions from vehicles, industry, power plants, waste, construction and household energy,” says Anumita Roychowdhury, executive director at CSE.

“What further stands out is the stubborn stability and the vast spread of the pollution levels across the NCR region as well as the worsening and proliferation of more pollution hotspots in the city. The tinier towns in the region display more intense and longer smog build up. Even though the peak pollution spikes are lower this winter due to lesser contribution of farm fires, the airshed is getting increasingly more saturated”, says Sharanjeet Kaur, deputy programme manager, Urban Lab, Clean Air unit, in CSE.

This CSE analysis is based on the air quality data accessed from the portal of the Central Pollution Control Board.