Delhi chokes day after Diwali, air quality plunges into ‘severe’ category, worst in 4 years

Delhi recorded its worst post-Diwali air quality in the last four years on Tuesday, with the Air Quality Index (AQI) plunging into the “severe” category. Major cities in Punjab and Haryana were also engulfed in haze.

According to data released by the Central Pollution Control Board (CPCB) on Tuesday evening, Delhi’s overall AQI stood at 351 and Gurugram’s at 370. At least 35 of 39 monitoring stations in the capital recorded readings in the “red zone”, which, according to the regulatory agency, can cause respiratory illness on prolonged exposure to pollutants.

The CPCB data showed that the overall level of PM2.5 in Delhi was 228 micrograms per cubic metre on Tuesday -- 15.1 times higher than the World Health Organisation’s (WHO) permissible limit of 15 micrograms per cubic metre in 24 hours.

The AQI scale categorises air quality as “good” between 0 and 50, “satisfactory” from 51 to 100, “moderate” from 101 to 200, “poor” from 201 to 300, “very poor” from 301 to 400, “severe” from 401 to 450 and “severe plus” above 450.

As per CPCB readings, Bawana recorded an AQI of 423 at 8 am, Jahangirpuri 397, and Wazirpur 394. Delhi’s air quality this Diwali was worse than last year’s 328, and higher than the previous two years — 218 in 2023 and 312 in 2022. In Manesar, the AQI was 320.

Jind recorded the worst air quality in Haryana with an AQI of 421, followed by Bahadurgarh at 368. Other cities also reported high pollution levels. Rohtak recorded 343, Bhiwani 307, Faridabad 249, Kaithal 290, Sonepat 255, Karnal 225, Kurukshetra 234, Panipat 231 and Sirsa 296.

In neighbouring Punjab, Ludhiana had the highest AQI at 271, followed by Jalandhar at 247 and Amritsar at 224.

A day before Diwali, on October 19, Delhi’s AQI had hit 296 and deteriorated thereafter. The Supreme Court had relaxed the ban on firecrackers to allow “green” crackers from 6 am to 7 am, and 8 pm to 10 pm on October 20 and 21. However, firecracker bursting continued well past midnight across Delhi-NCR. Several private air monitoring agencies recorded AQI levels above 1,000 in parts of the capital.

Swiss air technology company IQAir claimed, “Delhi is currently the most polluted major global city with an AQI of 1,121 and is experiencing one of its most polluted days in at least five years.”

“Diwali celebrations lead to increased use of fireworks, contributing heavily to airborne pollutants. This seasonal spike combines with pollutants from ongoing agricultural practices such as stubble burning and vehicular emissions, intensifying the air pollution crisis in northern India. While firecrackers are banned or restricted in several states, including Delhi, these remain in wide use,” it said.

Former NITI Aayog CEO Amitabh Kant said, “Delhi remains among the world’s most polluted capitals. If Los Angeles, Beijing and London can control it, why can’t Delhi? Only ruthless and sustained execution can save Delhi from this health and environmental catastrophe.”

He stressed the need for a unified action plan -- to end crop and biomass burning, modernise thermal power plants and brick kilns, shift all transport to electric by 2030, enforce strict dust control at construction sites, ensure full waste segregation and processing, and redesign Delhi around green, walkable, transit-focused living.

Speaking to The Tribune, Dr Gufran Beig, chair professor at the National Institute of Advanced Studies (NIAS), said air quality in Delhi-NCR began improving after 5 am on Tuesday. “Farm fire incidents have not been severe this year or the problem would have been much worse. Diwali this year is celebrated at a time when winter has not fully set in. Had it been celebrated in November, conditions would have been far more severe. Weather conditions in North India are still not entirely conducive for pollutants to accumulate, as winds tend to slow down after the monsoon withdrawal. That phase has already passed,” he said.