On Diwali night, Air quality in Delhi-NCR turns “severe”

The air quality in the national capital and surrounding areas dipped to "severe" on Saturday as people violated a ban on using Diwali firecrackers in several areas, compounding the pollution caused by burning farm waste in neighbouring states.

The national capital recorded an overall Air Quality Index or AQI of 414 on Saturday, which falls under "severe" category. The 24-hour average AQI was 339 on Friday and 314 on Thursday.

But two factors smoke from farm fires and stagnant surface winds will keep the air quality in the higher end of the very poor category to the lower end of the severe on Diwali night, it said.

Transport-level winds have become northwesterly and the stubble burning-induced impact on air quality index (AQI) is expected to increase, the central government agency said.

A spike in PM2.5 levels in the early hours Sunday is likely if fire crackers are burnt, it said.

The city recorded an AQI of 369 at 9 am on Saturday. The 24-hour average AQI was 339 on Friday and 314 on Thursday.

The neighbouring cities of Faridabad (323), Ghaziabad (412), Noida (362), Greater Noida (350), and Gurgaon (338), which fall in the National Capital Region (NCR), also recorded their AQI is the "very poor" and severe categories.

Delhi recorded a 24-hour average AQI of 337 on Diwali last year (October 27), and 368 and 400 the next day. Thereafter, pollution levels remained in the severe category for three days on the trot.

Residents complained about stinging eyes, sore throat and breathlessness as the city grappled with the third wave of the coronavirus pandemic.

Calm winds have worsened the situation, allowing the accumulation of pollutants, weather officials said.

The Ministry of Earth Sciences' air quality monitor, SAFAR, said, "Even a small increase in local additional emissions is likely to have significant deterioration impact on Sunday and Monday."

It said peak levels of PM10 and PM2.5 are expected between 1 am and 6 am in case of additional internal emissions.