- Better wind speeds and rain aided pollutant dispersion.
New Delhi: Delhi’s air quality was recorded in the ‘poor’ category on Sunday, with the Air Quality Index (AQI) settling at 290 at 4 pm, after several days of toxic air quality that had kept the national capital shrouded in a haze of pollution following Diwali.
Of the 58 air quality monitoring stations in the city, 34 recorded ‘poor’ air quality and 23 ‘very poor,’ while one (Delhi Cantonment) recorded ‘moderate’ air quality. NSIT Dwarka recorded the worst air quality with an AQI of 364.
In the morning, the city’s air quality stood in the ‘very poor’ category, with an AQI reading of 350, according to the Sameer app.
According to the Central Pollution Control Board (CPCB), an AQI between zero and 50 is classified as ‘good’, 51 and 100 as ‘satisfactory’, 101 and 200 as ‘moderate’, 201 and 300 as ‘poor’, 301 and 400 as ‘very poor’, and 401 and 500 as ‘severe’.
The city’s air quality had remained in the ‘very poor’ category since November 11, with several hourly readings during this period getting close to the ‘severe’ mark and even crossing it once.
The last time Delhi recorded a ‘poor’ AQI was on November 10, when it stood at 299. Before that, the AQI was recorded at 261 on November 1.
According to the real-time source apportionment of PM2.5 by the Air Quality Early Warning System and the Integrated Decision Support System, biomass burning emerged as the largest contributor to Delhi’s pollution on Sunday, accounting for 37.1 per cent. This category includes stubble burning, domestic solid biofuel and the burning of dung cakes and wood.
Secondary organic aerosols — fine particulates that form in air through chemical reaction of gases — were the second-largest contributor at 22 per cent, followed by vehicular emissions at 17.2 per cent and secondary inorganic aerosols at 9.6 per cent. Waste burning, including municipal waste and plastic- and rubber-containing waste, contributed 5.5 per cent, while mixed combustion accounted for 4.3 per cent.
Mineral dust and ash contributed 2 per cent, firecrackers 1.6 per cent and industrial emissions 0.6 per cent, the data showed.
The Air Quality Early Warning System has forecast that Delhi’s air quality is likely to be in the ‘poor’ category on November 16, before returning to the ‘very poor’ category from November 17 to 18. The air quality is likely to be ‘very poor’ for the subsequent six days, it said.
Weather experts attributed the change in air quality on Sunday to better wind speeds and light rainfall, which aided the dispersion of pollutants.
According to the India Meteorological Department (IMD), very light rain or drizzle was recorded at several places in Delhi during the past 24 hours, with surface wind speeds reaching up to 15 kmph from the southwest direction.
Generally cloudy skies, becoming partly cloudy towards the afternoon, prevailed over the region on Sunday, with surface winds reaching speeds of up to 10 kmph from the southwest, the weather department said.
The IMD’s forecast bulletin also said the ventilation index over Delhi is likely to decline from 16,000 square metres per second on November 15 to 15,000 on November 16, 7,500 on November 17 and 6,000 on November 18.
A ventilation index below 6,000 square metres per second, coupled with an average wind speed of less than 10 kmph, is considered unfavourable for the dispersion of pollutants, the bulletin said.
(This report has been published as part of the auto-generated syndicate wire feed. Apart from the headline, no editing has been done in the copy by ABP Live.)
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