AQI tops 400-mark, Delhi sees 1st ‘severe’ air day of the season

Residents woke up to another day of burning eyes and respiratory difficulties as the air quality index (AQU) in the national capital, which has been shrouded in a haze of toxic pollutants for days now, officially crossed the 400-mark, dipping into the ‘severe’ category for the first time this season.

- Jasjeev Gandhiok

Delhi's 24-hour rolling average AQI stood at 428 at 4 pm, when the Central Pollution Control Board releases its daily national bulletin — the highest since December 19 last year — prompting the Commission for Air Quality Management (CAQM) to invoke Stage 3 of the Graded Response Action Plan (Grap) across NCR with immediate effect. This enforcement includes aban on private construction and demolition work and restrictions on BS-3 petrol and BS-4 diesel four-wheelers in Delhi, Gurugram, Faridabad, Ghaziabad, and Gautam Budh Nagar.

Experts attributed the severe pollution to dipping temperatures and a drop in wind speed, which create an inversion layer that traps pollutants near the surface. “Winds started to drop on Monday and were almost calm through the night. We also have dipping temperatures, which led to significant accumulation of pollutants,” said Mahesh Palawat, vice president at Skymet.