NEW DELHI: Delhi’s air quality improved significantly to the “moderate” category on Monday morning owing to rain and strong winds.
A government forecasting agency said the air quality is likely to improve further to the “satisfactory” category.
The national capital’s air quality index (AQI) was 148 at 10 am. The 24-hour average AQI was 354 on Sunday and 443 on Saturday.
Officials at the India Meteorological Department (IMD) said intense rains lashed Delhi and winds gusting up to 30 kmph swept the city on Sunday under the influence of a strong Western Disturbance affecting northwest India, dispersing pollutants.
The Safdarjung Observatory recorded 39.9 mm rainfall between 8:30 am on Saturday to 2:30 pm on Sunday.
More rain is likely on Monday. The maximum wind speed will be around 30 kmph, the IMD said.
The central government’s Air Quality Early Warning System for Delhi said the AQI is likely to remain “moderate” to “satisfactory” on Monday and Tuesday.
It said the city’s ventilation index — a product of mixing depth and average wind speed — would be 5,000 m2/s on Monday and Tuesday.
Mixing depth is the vertical height at which pollutants are suspended in the air. It reduces on cold days with calm wind speed.
A ventilation index lower than 6,000 sqm/second, with the average wind speed less than 10 kmph, is unfavourable for the dispersal of pollutants.
NCR AQI improves too
After a spell of rain, the average air quality improved from “very poor” to ‘moderate’ levels in Ghaziabad, Noida, Greater Noida and Faridabad, while it reached ‘satisfactory’ category in Gurgaon.
Gurgaon and Faridabad last had a ‘moderate’ air day on December 15, Noida on December 14, Greater Noida and Ghaziabad on November 27, official figures from corresponding dates showed.
(With PTI inputs)