Post-Diwali Air Quality Declines Sharply in Delhi and Kolkata

PTI, NEW DELHI/KOLKATA, OCT 21, 2025 :  The air quality in Delhi plummeted on Tuesday post-Diwali as residents flouted the Supreme Court-mandated time slots for bursting of firecrackers, even as the city government blamed the AAP dispensation in Punjab for the toxic haze over the national capital, alleging forced stubble burning last night.

The city recorded its worst air quality on Tuesday since 2021, with PM2.5 levels reaching 488 micrograms per cubic metre in the 24 hours after Diwali—more than three times the pre-festival level of 156.6 micrograms per cubic metre. In neighbouring Haryana too, the air quality deteriorated, with the AQI falling in the 'very poor' category in many areas, including in Gurugram, while it was in the 'poor' category in most parts of Punjab.

According to an analysis of Central Pollution Control Board (CPCB) data covering the period from 2021 to 2025, PM2.5 values in Delhi consistently spiked during Diwali night and early the next morning, with the 2025 post-Diwali reading of 488 micrograms per cubic metre being the most polluted period since 2021. The data shows that in previous years, average PM2.5 levels rose from 163.1 to 454.5 in 2021, from 129.3 to 168 in 2022, from 92.9 to 319.7 in 2023 and from 204 to 220 in 2024.

In Kolkata, the air quality remained 'poor' on Tuesday due to the bursting of firecrackers on Kali Puja the previous night. Environmentalists alleged that particulate matter hung in the air after firecrackers were burst beyond the permissible hours of 8 PM to 10 PM till midnight across the metropolis, flouting guidelines issued by the West Bengal Pollution Control Board (WBPCB) and police.

A WBPCB official said that the AQI was 253 (PM2.5) at the air monitoring station at Victoria Memorial at 2 PM on Tuesday, higher than 186 on Monday midnight. However, Kolkata Police Commissioner Manoj Verma on Tuesday claimed that both noise and air pollution levels in the metropolis during Diwali were significantly lower this time as compared to last year. Verma claimed that the city also fared better than other metropolises in this regard.

According to the Police Commissioner, Kolkata witnessed fewer violations of norms laid down for the celebrations, and enforcement teams patrolling various neighbourhoods confirmed that pollution control was better this year. "Noise levels remained under 90 decibels, well within the permissible limit of 125 decibels. Till 6 PM on Monday, air quality in Kolkata was better than in most other major cities in India. A clearer picture will emerge once data from 10 PM or midnight is reviewed," Verma told reporters.

However, the ground situation told a different story.