Delhi’s pollution level drops to ‘severe’ category; dense fog expected

The air quality in Delhi on Monday was the worst compared to nine other cities monitored on the central pollution control board’s website

Pollution levels were in the “severe” category in Delhi on Monday morning with an hourly air quality index (AQI) of 407 at 7am. The average 24-hour AQI on Thursday was 353 in the ‘poor’ category. The air quality in Delhi on Monday was the worst compared to nine other cities monitored on the central pollution control board’s website.

On Sunday, the minimum temperature was 6.2°C, two notches below normal. (File image)

An AQI between zero and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, and 401 and 500 severe. The AQI in the ‘very poor’ category can lead to respiratory illness on prolonged exposure.

On the weather front, dense fog is expected on Monday with a minimum temperature of around 6°C and a maximum of 24°C. On Sunday, the minimum temperature was 6.2°C, two notches below normal, and the maximum temperature of 23.7°C.

On Sunday, the union ministry of earth science’s air quality monitoring centre, system of air quality and weather forecasting and research (Safar) said, “Overall AQI today indicates ‘very poor’ air quality. Fine particles (size < 2.5 micrometer) contribute ~ 57% to PM10. For the next 3 days, surface wind speed (calm to 12 km/h) and temperature (Max Temperature 24 deg C; Min 6 °C are likely to increase AQI. Mixing layer height is likely to be ~ 1.0 km that helps dilution of pollutants. Air quality is likely to deteriorate but be within ‘very poor’ for the next 3 days due to decreasing temperatures and low wind speed resulting in weak dispersion of pollutants.”