Delhi: Strong surface winds improve air quality

New Delhi: The Capital's air quality continued to remain in the 'poor' category on Saturday morning, aided by strong surface winds, which had markedly improved Delhi's air quality a day before. The city's air quality index (AQI) stood at 235 (poor) at 8am, as compared to the 24-hour average AQI of 236 recorded at 4pm on Friday, according to data from the Central Pollution Control Board (CPCB).

Delhi's air quality on Friday improved by more than a 100 points from Thursday's reading of 380 (very poor) at 4pm. This prompted the Commission for Air Quality Management (CAQM) to lift stage-3 measures of the Graded Response Action Plan (Grap) with immediate effect in NCR on Friday evening.

According to forecasts by the Air Quality Early Warning System (AQEWS) for Delhi, the air quality could deteriorate in the next few days.

"The air quality is likely to be in the poor category on Saturday. The air quality is likely to be in the very poor category from Sunday to Monday. The outlook for the subsequent six days is that the air quality is likely to be in the very poor category," the AQEWS bulletin said.

The CPCB classifies air quality as “moderate” when the AQI is between 101 and 200, “poor” between 201 and 300, and “very poor” between 301 and 400. Beyond 400, air quality is termed “severe”. For the purpose of Grap, stage-3 measures kick in if the AQI is forecast if it crosses 400. Stage-4 can meanwhile be imposed if the AQI is forecast, or crosses 450.

The cold northwesterly winds currently impacting the region is expected to lead to a drop in the minimum temperature in the following days, according to the forecast by the India Meteorological department (IMD). The Met department has also issued a yellow alert for Sunday, warning people of a moderate fog to persist in the late evening hours.

The minimum temperature on Saturday stood at 8.1 degrees Celsius, 1.2 drgree above the normal and a degree lower than a day before. This is forecast to further dip by a couple of degrees over the weekend and should hover between 6-8°C for the next few days, according to Met officials.

The maximum meanwhile stood at 17.4°C on Friday and is expected to remain in the 17-19°C range on Saturday as well.

According to the flight tracking website FlightRadar24, The Delhi airport saw at least 150 flight delays on Saturday morning. Airport officials said this was predominantly due to impact at other airports, including several in north India where visibility fell to zero.

The IMD has forecast dense to very dense fog conditions to continue over Punjab, Haryana, Chandigarh, Uttar Pradesh, Bihar and Odisha for 5-7 days, while it is likely in parts of Jammu, Himachal Pradesh, Uttarakhand, Rajasthan, north Madhya Pradesh and Northeast India over the next 4-5 days.