Delhi

Rain washes away pollutants but air quality stays very poor

Staff Reporter

With a spell of rain on Sunday, pollution level  dipped marginally, however, the air quality remained in the ‘very poor’ category, authorities said.

According to authorities, Delhi’s air quality improved significantly and it was recorded lowest of the current month on Sunday after rainfall washed away pollutants.

According to the Central Pollution Control Board (CPCB) data, the overall Air Quality Index (AQI) in the city was 338. Adjoining districts such as Ghaziabad, Faridabad, Gurugram and Noida  too recorded ‘very poor’ air quality, it said.

Delhi’s air quality has been oscillating between upper range of ‘very poor’ and ‘severe’ category for the past two weeks.

Thirty-one areas in Delhi recorded ‘very poor’ air quality on Sunday, while in two areas it was ‘poor’, the (CPCB) data revealed.

The overall PM2.5 level (fine particulate matter in the air with a diameter of less than 2.5 micrometers) in Delhi was recorded at 184 while the PM10 (fine particulate matter in the air with a diameter of less than 10 micrometers) level was at 274, the CPCB said. An AQI between 100 and 200 comes under ‘moderate’ category, 201 and 300 is considered ‘poor’, 301 and 400 ‘very poor’, while that between 401 and 500 is ‘severe’.              

The Centre-run System of Air Quality and Weather Forecasting (SAFAR) said the overall air quality in Delhi was ‘very poor’.

“The rainfall along with sufficient wind speed was enough to wash away air pollutants to an extent and improved the AQI.

Air quality is likely to improve much faster during the day as moderate surface wind speed is positively working to disperse pollutants which are the key factor now in keeping pollution in check under cool and foggy weather conditions,” the SAFAR said.

It, however, noted that the respite is not expected to last longer than two days as relative humidity is very high and temperature is likely to drop further which will force boundary layer to come down and will hold pollutants near the surface.

The AQI will start to increase gradually from Tuesday but will continue to remain in ‘very poor’ range, SAFAR said.