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Despite a significant 77 per cent reduction in stubble burning due to floods in Punjab and Haryana, Delhi's air quality remains dire post-Diwali.
The capital's PM 2.5 levels soared to severe levels after the festival, highlighting that reducing farm fires alone is insufficient.
Local emissions, particularly from fireworks, continue to be a major contributor to the city's pollution crisis.
Despite a historic 77 per cent plunge in stubble burning incidents this October due to unprecedented floods in Punjab and Haryana, Delhi’s air quality has failed to breathe easily. The Capital’s PM 2.5 levels, though slightly lower earlier in the month, spiked to “severe” levels following Diwali celebrations — revealing that curbing farm fires alone isn’t enough to clean Delhi’s toxic air.
According to a comparative analysis of satellite fire data, Central Pollution Control Board (CPCB) readings and Climate Trends, Punjab and Haryana together recorded just 175 stubble burning incidents between October 1–12 this year, down from 779 in the same period last year. This massive 77.5 per cent decline was primarily driven by flood-induced waterlogging that delayed paddy harvesting and prevented farmers from torching crop residue.
Consequently, Delhi’s average PM 2.5 concentration in the first half of October 2025 dropped 15.5 per cent compared to 2024, falling from 60.79 µg / m³ to 51.48 µg / m³, data from the analysis show. However, the relief was short-lived.
As Diwali approached, pollution levels spiraled. The CPCB’s network recorded an average post-Diwali PM 2.5 of 488 µg / m³ — the highest in five years — with late-night peaks exceeding 675 µg / m³, categorised as “severe-plus emergency” by the Graded Response Action Plan (GRAP).
“The floods gave us a rare natural experiment — proof that fewer farm fires lead to cleaner air. But the Diwali spike proves that local emissions, especially fireworks, can instantly wipe out those gains,” said Palak Balyan, Research Lead at Climate Trends. “Post-Diwali readings were more than three times the pre-festival average of 156.6 µg / m³. Clearly, we cannot rely on external factors like floods or wind to fix our air.”
Satellite data from NASA’s FIRMS platform confirms the drop in biomass burning across Punjab and Haryana. On October 12, 2024, both states reported 232 fire events, coinciding with Delhi’s highest PM 2.5 reading of 74.79 µg / m³ that season. In contrast, October 12, 2025, saw only 21 fire events and a similar PM 2.5 level of 63.66 µg / m³, highlighting how urban sources are now the dominant contributors.
“Even with fires curbed, Delhi’s PM 2.5 never fell below 22 µg/m³ this month — well above WHO’s safe limit,” said a senior official from the Delhi Pollution Control Committee (DPCC). “This background pollution shows how much of the city’s burden now comes from vehicles, industries, and dust resuspension.”
2025 trends: Weaker correlation
Meteorological conditions worsened the post-Diwali crisis. According to SK Dhaka, professor at Rajdhani College, University of Delhi, “Wind speed during Diwali night was below 1 m / s, with high humidity levels of 60–90 per cent. These stagnant conditions trapped pollutants close to the surface, preventing dispersion. The rise was purely local — not transported from outside.”
Temperature data reinforces this. Delhi’s average post-Diwali temperature dropped to 20°C, compared to 27°C pre-Diwali, amplifying temperature inversion effects — when cold air traps pollution under a warm layer above.
The twin datasets together offer a stark reality check. Despite floods acting as a “forced intervention” that slashed farm fires, Delhi’s air remained hazardous — proving that focusing solely on agricultural burning cannot deliver clean air.
“The 2025 floods unintentionally achieved what enforcement couldn’t: a 77 per cent drop in fires. Yet, Delhi still choked. That’s the real warning,” said Aarti Khosla, Founder and Director, Climate Trends. “Until we tackle vehicular emissions, construction dust, and fireworks with equal urgency, we’ll be stuck in this annual cycle of blame and smog.”
While Delhi briefly saw cleaner skies in early October, the respite vanished within hours on Diwali night. Pollution maps lit up red, and visibility plummeted across the NCR. Hospitals reported a surge in respiratory complaints.
Experts now warn that 2025’s post-flood, post-Diwali data should serve as a wake-up call. “Nature gave us a glimpse of what clean air could look like,” said a CPCB scientist. “But it also showed us that without behavioural change and year-round control, those gains can vanish overnight.”