Delhi’s air quality hovers at ‘very poor’ category

According to the central pollution control board (CPCB), the hourly air quality index (AQI) was 322 at 7am

Delhi’s air quality remained in the ‘very poor category’ on Monday morning as mist was expected along with minimum temperature of 8°C.

On Sunday, the average 24-hour AQI was 328. (HT file photo)

According to the central pollution control board (CPCB), the hourly air quality index (AQI) was 322 at 7am. On Sunday, the average 24-hour AQI was 328.

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’.

On Sunday, the government’s monitoring agency system of air quality and weather forecasting and research said, “Overall AQI today indicates ‘Very Poor’ air quality. Pollutants emitted from stubble burning contribute 2% to PM2.5 in Delhi. Fine particles (size < 2.5 micrometer) contribute ~ 54% to PM10. Local surface winds being moderate (6-10 km/h) cause moderate dispersion while drop in minimum temperature (max temperature 27-26°C; min 8-7°C) helps accumulation of pollutants. Moderate ‘Mixing layer height’ during daytime (~ 1.0–1.5 km) enhances vertical mixing. AQI is likely to remain within ‘Very Poor’ today. For the next 3 days, upper level winds are from northwest direction that is expected to enhance transport of pollutants from stubble burning region if fire counts increase. AQI is likely to be within ‘Very Poor’ for the next 3 days due to the net effect of transport, local emissions and efficiency of dispersion and ventilation.”

On the weather front, the minimum temperature is likely to be 8°C while the maximum at 27°C.

The minimum temperature on Sunday was 7.9°C, two notches below normal, and the maximum was 27.5°C, two notches above normal.