Deepavali fireworks worsen Delhis air high quality

Following Deepavali, air pollution in Delhi inched near a five-year low with common concentrations of particulate matter (PM) 2.5 throughout a number of places crossing 400 microgram per cubic metre (µg/m³) – ranges not seen since 2021.

On Deepavali day, 9 cities out of the 293 monitored by the Central Pollution Control Board (CPCB) reported an air high quality index (AQI) worth of above 300, classed as ‘very poor’ air high quality. On the day after Deepavali, Tuesday (for a lot of the nation), this rose to 16 cities, in response to information accessible on the organisation’s web site. Nearly all of those fell in north India and within the Indo-Gangetic plains. Nationally, Dharuhera in Haryana reported the worst air high quality index studying of 462 on Tuesday (October 21, 2025).

Sharp spike

An evaluation of PM 2.5 tendencies, which was recorded by CPCB’s automated air high quality sensors, by unbiased weather-and-climate company, Climate Trends, confirmed a pointy spike in particulate matter focus from 4 p.m. on Deepavali day (October 20) in Delhi. From values of round 150 at 4 p.m., it spiked to just about 650 by 11 p.m. This coincides with the interval throughout which bursting firecrackers was legally permissible ( 8 p.m. to 10 p.m.) on Deepavali day, per the reprieve by the Supreme Court.

The SC, in its order, had allowed the usage of solely CSIR-validated ‘inexperienced crackers’, which reportedly exudes a minimal 30% much less smoke than their conventional counterparts. However, the sheer quantity of fireworks through the interval, anecdotal reviews of the unavailability of those firecrachers, and the air high quality index of the day following Deepavali (Tuesday), counsel that these norms had been violated.

A key parameter that determines air high quality ranges are wind speeds on the pageant night time in addition to temperatures. When night time temperatures are low, smoke and chemical pollution hover like haze and won’t rise to increased reaches of the environment and get flushed out. Temperatures on Deepavali night time this 12 months ranged from 23-25 diploma C, the warmest in 5 years however low wind speeds and the amount of smoke retarded its egress out the Delhi and the Gangetic plain airshed.

“When examined collectively, PM 2.5 and temperature information reveal a constant sample: excessive emissions from fireworks and low night-time temperatures collectively contribute to elevated PM 2.5 concentrations. The sharp post-Deepavali spikes point out each sustained emissions and poor atmospheric dispersion,” the Climate Trends report notes.

“The Diwali of 2025 was one of the polluted in recent times. The spike between the nights of the nineteenth and twentieth instantly corresponds to the widespread use of firecrackers throughout Delhi-NCR. Moreover, visuals and floor information verify that burning so-called ‘inexperienced’ crackers made no measurable distinction in comparison with common ones. It’s now evident that permitting firecrackers throughout this time of 12 months is solely not sustainable for the NCR area’s already important air high quality,” Palak Balyan, Research Lead, Climate Trends, mentioned in an announcement.

A perusal of the AQI values on Deepavali and the following day on the CPCB web site present that in 2023, Delhi’s post-Deepavali (November 13) AQI was 358 (very poor) – near the 351 (very poor) reported at 4 p.m. this 12 months. The five-year document, nevertheless, was on November 5 in 2021, when it recorded 462 (‘extreme’). Deepavali AQI this 12 months within the metropolis was 345, solely topped by Deepavali AQI of 382 on November 4, 2021.

The CPCB presents an annual report of air high quality and noise-pollution ranges nationally on Deepavali night time and following day. It is predicted later this week. The Environment Ministry didn’t supply any remark or evaluation of the Delhi air high quality on Tuesday.