Delhi chokes on ‘very poor’ air for 12th consecutive day
The 24-hour average AQI was at 338 (‘very poor’) at 10pm on Sunday, which was marginally lower than Saturday’s 4pm reading of 352.
The city’s air was dense with pollutants and remained hazy on Sunday too, recording a 12th consecutive day of “very poor” air quality index, as categorised by the Central Pollution Control Board’s (CPCB’s) daily bulletin, in line with predictions by air monitoring and weather agencies.
The 24-hour average AQI was at 334 (‘very poor’) at 4pm on Sunday, which was marginally lower than Saturday’s 4pm reading of 352 (‘very poor’), data showed. At 10pm, it rose slightly to 338.
The readings will likely hover in the ‘very poor’ category till at least Wednesday, as forecasts show that winds are expected to remain calm overnight, with smog likely in early morning hours. On Sunday too, the India Meteorological Department (IMD) said that Delhi reported smog conditions through a majority of the day, with visibility dipping to as low as 700 metres, as recorded at 7am at the Safdarjung observatory.
IMD classifies it as fog if visibility is below 1,000 metres, but it can be termed smog if relative humidity is less than 75%. “Mainly smog conditions with wind speed of 4 to 10 kmph were reported from the southeasterly, easterly direction in the forenoon,” IMD said in its daily forecast bulletin.
Winds have largely been remaining calm overnight, but pick up marginally during the day, with similar conditions reported on Saturday too. Delhi’s AQI peaked to 390 (‘very poor’) — on the cusp of ‘severe’ AQI (400+) — on Friday, before it began improving as wind speed also picked up.
An IMD official said that wind speed is expected to drop marginally once more on Monday, with chances of fog in the early hours of the day and smog towards late evening and night-time. “Winds should be between 4-6 km/hr during the day and almost calm at night,” the official said.
Meanwhile, PM2.5 (particulate matter with a diameter of 2.5 microns or less) was the major pollutant on Sunday, according to CPCB — suggesting that combustion was the predominant source of pollution. None of the 36 operating air quality stations recorded AQI in the “severe” range or beyond the 400-mark at 4pm. The highest AQI of 392 during the day was recorded at the Bawana station, and the lowest was recorded at Aurobindo Marg and Chandni Chowk stations, at 206 each.
The contribution of farm fires to Delhi’s PM2.5 concentration on Saturday was unavailable. On Friday, it was 20.5% and 17.8% a day earlier. With the wind direction predominantly staying southeasterly in the coming days, the contribution is expected to drop again.
Forecasts by the Centre’s Early Warning System for Delhi (EWS) showed no significant change in AQI in the coming days. “Delhi’s AQI is likely to stay ‘very poor’ till Wednesday,” it said.
The temperature, meanwhile, also continued to remain higher than normal. The maximum was 31.6°C on Sunday — two degrees above normal but 0.9°C lower than Saturday. The minimum was 18.4°C, four notches above normal. It was 18.3°C a day earlier. Forecasts show the maximum is likely to oscillate between 32-33°C till Wednesday, while the minimum will be between 17°C and 18°C, the IMD said.