Air pollution: Strong winds bring temporary relief in Delhi; AQI improves

Strong surface winds barrelled through Delhi and neighbouring areas on Monday, improving the air quality.

The city recorded its 24-hour average air quality index (AQI) at 311, down from 349 on Sunday. It was 374 on Saturday. Neighbouring Faridabad (330), Ghaziabad (254), Greater Noida (202), Gurgaon (310) and Noida (270) also recorded a slight improvement in the air quality.

R.K. Jenamani, a senior scientist at the India Meteorological Department (IMD), said westerly winds gusting up to 25 kmph improved visibility to 3,200 metres.

So far, Monday has been the only day in November when the Palam Observatory reported "visibility of more than 3,000 m and such strong winds", he said.

The ministry of earth sciences air quality monitor SAFAR said the AQI was recorded in the lower end of the "very poor" category on Monday, a "significant" improvement from the day before due to the low fire count and strong transport-level winds blowing from northwest direction dispersing pollutants.

These winds are likely to continue on Tuesday, leading to further improvement in the air quality to the 'poor' category (if no increase in fire count), it said.

Local surface wind speed is also relatively high on Monday and will remain so on Tuesday, it said, adding that local and transport-level winds are likely to slow down from Wednesday and result in slight deterioration in the air quality.

SAFAR said 909 farm fires accounted for 6 per cent of Delhi's PM2.5 pollution on Monday.

The minimum and maximum temperatures were recorded at 27.5 degrees Celsius, a notch above the season's average and 11.4 degrees Celsius, normal for this time of the year. The weatherman has forecast mainly clear sky for Tuesday with mist in the morning. The maximum and minimum temperatures are likely to settle at 26 degrees and 11 degrees Celsius, respectively.