With safety at stake, many in the national capital defied the cracker-ban, turning the air quality in the region to "severe" with stubble burning accounting for 32 per cent of Delhi's PM2.5 pollution. At Air Quality Index (AQI) at 414, Delhi recorded the worst air quality in four years. Last year, the city recorded a 24-hour average AQI of 337 on Diwali last year and 268 and 400 in the subsequent two days. In 2018, the 24-hour average AQI was 281 on Diwali, deteriorated to 390 the next day and remained "severe" on three consecutive days. Likewise in 2019, Delhi's 24-hour average AQI on Diwali was 319. Earlier, the Ministry of Earth Sciences' air quality monitor, SAFAR, had said that the PM2.5 concentration in Delhi on Diwali was "likely to be the lowest" of the last four years if no firecrackers were burnt.
According to the Graded Response Action Plan (GRAP), the air quality is considered in the "severe plus" or "emergency" category if PM2.5 and PM10 levels persist above 300 µg/m3 and 500 µg/m3 respectively for more than 48 hours.
A LOOK AT AQI IN DELHI
ASHOK VIHAR: 492
North Campus, DU
ANAND VIHAR: 476
Meanwhile, the India Meterological Department has said that a fresh western disturbance is likely to increase the wind speed and improve the air qualuty in Delhi-NCR post Diwali. According to Kuldeep Srivastava, the head of the IMD's regional forecasting centre, light rain is likely on Sunday under the influence of a western disturbance. "It is still to be seen if it is enough to wash away pollutants," he said.
The Air Quality Early Warning System for Delhi has also said the situation is likely to "improve significantly" on Sunday. "Under the influence of a Western Disturbance, isolated rainfall over plains of northwest India and adjoining central India is likely on Sunday. The predominant surface wind is likely to be coming from East-Southeast direction of Delhi with wind speed up to 20 kmph," it said. "Generally cloudy sky, light rain, thundershowers accompanied with gusty winds (speed 30-40 kmph) is likely towards afternoon-evening on Sunday," the central agency said.