‘Green’ crackers fail, Delhi chokes’: Post-Diwali smog hits four-year high, PM2.5 peaks at 675

Delhi woke up on Tuesday under a blanket of grey haze and acrid air, recording its worst post-Diwali air quality in four years with PM2.5 levels peaking at 675 micrograms per cubic metre — the highest since 2021.

- AIMAN FATIMA

This came despite the Supreme Court allowing the bursting of ‘green’ firecrackers within specified hours, as celebrations reportedly continued well past the 10 pm deadline, leaving the Capital engulfed in smog and a swirl of political recriminations.

According to the Central Pollution Control Board (CPCB), Delhi's 24-hour average Air Quality Index (AQI) at 4 pm on Diwali stood at 345, classified as “very poor’, compared to 330 in 2024, 218 in 2023, 312 in 2022, and 382 in 2021. By Tuesday afternoon, the AQI remained almost unchanged at 351. Hourly readings showed sustained high pollution through the night — 344 at 10 pm, 349 at midnight, and above 350 through the next morning.

The PM2.5 concentration, representing fine particles that can deeply penetrate the respiratory system, climbed steadily through the evening—from 91 micrograms per cubic metre at 5 pm to 371 at 9 pm, 537 at 10 pm, and eventually 675 by midnight. For comparison, PM2.5 levels were 609 in 2024, 570 in 2023, 534 in 2022, and 728 in 2021. Experts noted that the readings far exceeded the safe limit of 60 micrograms per cubic metre.

‘The Decision Support System (DSS), Delhi’s pollution source tracker, reported that transport emissions contributed 14.6 per cent to the city's air pollution on Tuesday, Neighbouring regions also added to the problem - Ghaziabad (6 per cent), Noida (8.3 per cent), and Gurugram (3.6 per cent). Stubble burning, though officially estimated at only 1 per cent contribution on the day, continued to dominate the political narrative.

"This is the thickest smog I've seen since 2021. My children are coughing constantly despite keeping all windows shut," said Meenakshi Sharma, a Dwarka resident.

"We followed all the rules - no firecrackers, air purifiers in every room and yet the air feels like poison." Doctors across the city reported a sharp rise in respiratory cases. "Outpatient visits doubled this morning," said Dr.