Delhi’s air remains very poor with no respite ahead; mercury to fall

Delhi's air quality remained "very poor" but improved slightly from the previous day.

Delhi’s air quality remained “very poor” on Friday but improved marginally from “near severe” levels a day ago even as the haze persisted and grey skies barely allowed the sun to break through.

New Delhi, India- December 01, 2023: Commuters on NH 24 in smoggy morning, in New Delhi, India, on Friday, December 01, 2023. (Photo by Sunil Ghosh / Hindustan Times)

The 24-hour Air Quality Index (AQI) was 372 (very poor) on Friday, according to the Central Pollution Control Board’s bulletin of 4pm. It was 398 (very poor) at the same time on Thursday.

Still, the difference between the two readings are largely academic, and the air on both days was bad enough to leave people with long-term illnesses.

With no change expected in meteorological conditions over the weekend — wind speed will likely touch 5-6 km/hr during the day and predominantly stay calm at night — AQI will remain “very poor” in the coming days, forecasts suggested.

“Delhi’s air quality is likely to remain in the ‘very poor’ category from December 2 to 4. The outlook for subsequent six days also shows the air quality is likely to remain in the ‘very poor’ category,” predicted the Early Warning System (EWS), a model used by the Commission for Air Quality Management (CAQM).

“Delhi may have been helped marginally on Friday as winds did not become completely calm at Palam during the night. Otherwise, we have not seen any change in meteorological conditions,” Kuldeep Srivastava, scientist at IMD, said.

IMD said that the wind direction in Delhi was currently northwesterly, which is expected to bring down the mercury further, making the outlook for the city’s air quality grimmer. Low temperatures mean that the air becomes heavier, accumulating pollutants.

On Friday, however, the temperatures rose slightly from a day ago and were above normal for this time of the year.

The minimum temperature was 13.3°C — three degrees above normal — against 12.6°C seen a day ago. The maximum was 25.4°C — a degree below normal and slightly higher than the 25.1°C a day earlier.

The city will get colder in the coming days, according to IMD. “The maximum is expected to remain around the 25 degrees mark, but the minimum will gradually start dipping again, touching 10°C by Tuesday,” Srivastava said.

Delhi also witnessed a moderate fog on Friday, with visibility dipping down to 400 metres in the early hours.

The Capital ended this November with nine “severe” air days — when the AQI was over 400 — but it has also recorded another nine days when the AQI has been on the brink of “severe” — an AQI between 390 and 400. The Capital, thus, recorded 18 days of “near severe” or “severe” air this month – the highest number of such days since 13 of them were recorded in November 2021 and 11 in November 2016, CPCB data showed.

CAQM on Thursday called an emergency meeting on the deteriorating air quality. However, Stages 3 measures of the Graded Response Action Plan (Grap) were not invoked, as it forecast an immediate improvement.

“The CAQM subcommittee noted that as per the air quality forecasts by IMD and the Indian Institute of Tropical Meteorology (IITM), Delhi’s average AQI will start showing improvement from Thursday itself. Therefore, after reviewing the overall air quality scenario and its relevant aspects, it was decided by the sub-committee unanimously to watch the situation for a day or more, before taking a decision on invoking stringent actions under Stage 3 of GRAP,” the body said in a statement on Thursday.