Winds provide some respite to Delhi from pollution

Delhi's air quality improved to "poor" with winds at 18 km/h, lowering AQI to 282, but is expected to return to "very poor" levels soon.

New Delhi

Foggy morning on the Delhi-Meerut expressway. (Sakib Ali/HT)

Strong winds of speeds touching 18 kilometres per hour (kmph) brought some respite to Delhi, cleaning up the air and bringing down the Capital’s air quality index (AQI) to “poor” level—only for the fourth time since November 1, since when it has largely remained in the “very poor” category.

The 24-hour average AQI was 282, according to the Central Pollution Control Board’s (CPCB’s) daily air quality bulletin released at 4pm. The AQI was 314 a day earlier. Also, the last time Delhi recorded a “poor” AQI day was on November 30, when the AQI was 279.

Weather forecasts have predicted winds of up to 20kmph on Wednesday, which is expected to further clean up the city’s air, but the AQI is predicted to slip back into the “very poor” level from Thursday.

“Delhi’s air quality is likely to be in the ‘poor’ category till December 10. The AQI is likely to be in the ‘very poor’ category from December 11 till December 12. The outlook for the subsequent six days - from December 13 shows AQI is likely to be between ‘severe’ and ‘very poor,” said the Centre’s Air Quality Early Warning System (EWS) for Delhi.

The CPCB classifies air quality as “moderate” when it is between 101 and 200, as “poor” when the AQI is between 201 and 300, and as “very poor” when it is between 301 and 400. Beyond 401, air quality is termed as “severe”.

Mahesh Palawat, vice president at Skymet, said the relief was temporary, largely due to strong winds. “We had wind speed touching 18 kmph on Tuesday and similar winds were seen on Monday too, which helps in dispersion,” he said.

Meanwhile, Delhi’s minimum temperature continued to rise on the day. Delhi recorded a minimum temperature of 9.2 degrees Celsius (°C) on Tuesday, which was a degree above normal. It was 8.7°C on Monday and 8°C on Sunday. The minimum has risen these last few days, due to a western disturbance impacting the region.

The maximum temperature was 25.5°C on Tuesday, which was a degree above normal. It was 26.3°C on Monday. Forecasts show a marginal dip in minimum temperature, by 1-2°C, is likely again by Thursday. The maximum temperature is also expected to dip by 2-3°C by the weekend.