Delhi's AQI 'very poor' again

New Delhi, Nov 6 (PTI) After two days of slight improvement, Delhi's air quality has worsened again, plunging back into the 'very poor' category on Thursday, with stubble burning emerging as a major contributor and no respite expected anytime soon.

The 24-hour average Air Quality Index (AQI), reported at 4 pm every day, stood at 311, placing Delhi in the 'red zone', according to data from the Central Pollution Control Board (CPCB).

Delhi ranked fourth among the most polluted cities, with Rohtak topping the list in the ‘very poor’ category with an AQI of 348 out of 254 cities, according to the CPCB.

On Wednesday, Delhi's air quality had shown some improvement with an overall AQI of 202, as favourable wind conditions helped disperse pollutants.

The AQI was 291 on Tuesday and 309 on Monday, the CPCB data showed.

Meanwhile, PM 2.5 remained the key pollutant on Thursday.

Of the 38 monitoring stations in the capital city, 32 reported air quality in the ‘very poor’ category, with readings above 300, according to the CPCB’s Sameer App.

Meanwhile, the Decision Support System (DSS) for air quality forecasting estimated that stubble burning contributed 21.5 per cent to Delhi’s PM2.5 levels on Thursday, likely to rise to 36.9 per cent on Friday and 32.4 per cent on Saturday, up from just 1.2 per cent on Wednesday.

Satellite data showed that on Wednesday, 94 stubble-burning incidents were detected in Punjab, 13 in Haryana, and 74 in Uttar Pradesh.

After stubble burning, transport was projected to be the second-highest contributor, accounting for 16.2 per cent on Thursday, 11.2 per cent on Friday, and 12.3 per cent on Saturday.

According to the Air Quality Early Warning System for Delhi, wind speed was expected to decrease to below 10 kmph from the northwest direction during the evening and night hours on Wednesday.

The air quality is likely to remain in the ‘very poor’ category between November 6 and 8, the forecast stated.

Since Diwali, the national capital's air quality has fluctuated between the ‘poor’ and ‘very poor’ categories, occasionally dipping into the ‘severe’ zone. PTI NSM SMV NB