Beyond the Burn: Delhi’s winter smog intensifies even after stubble fires fade

January 02, 2026

A new analysis by the Centre for Science and Environment (CSE) sheds light on the shifting air quality trends in Delhi and the National Capital Region (NCR). The study compares the "early winter" months of October and November—a period heavily influenced by farm fires—with the "post-farm fire" period of December, when the impact of stubble burning becomes negligible and finds that the post-stubble burning phase has experienced intense, widespread smog across the NCR – more severe than the stubble burning period.

These findings reveal a concerning reality: Delhi’s winter pollution does not dissipate once stubble burning ends; instead, it intensifies. Despite the farm-fire contribution to PM2.5 levels dropping sharply in December the average PM2.5 levels have actually increased. The stark contrast between declining fire influence and rising pollution levels across Delhi and NCR indicates dominance of local and regional sources—vehicles, industry, waste burning, solid fuels for domestic cooking and heating. While managing farm fires is important, air quality goals cannot be met without aggressive, year-round action against urban and regional emission sources for zero emissions transition. The smog is a combination of local emissions, regional inflows, and secondary aerosol formation, requiring coordinated airshed-level action alongside aggressive control of local sources.