NEW DELHI: Despite light rain in parts of the city, Delhi’s air quality deteriorated slightly further on Monday, December 7, 2021, as winds remained slow not allowing enough ventilation for the dispersion of pollutants. Air quality is likely to remain so over the next two days, said weather officials.
As per the Central Pollution Control Board (CPCB), Delhi’s overall air quality index (AQI) on Sunday was 322, as against 305, the previous day. Delhi has been experiencing high levels of pollution since November.
The union government’s System for Air Quality and Weather Forecasting and Research (SAFAR) said: “The AQI remained in the lower end of very poor zone owing to rain in some parts of the city last night. For the next two days, winds are likely to be moderate increasing ventilation. However, minimum temperatures are likely to drop gradually leading to a more stable atmosphere reducing convective mixing. The net effect is that air quality remains within ‘upper end of poor’ or lower end of ‘very poor’. On December 8-9, winds are expected to be low and AQI is likely to remain in ‘very poor’ category. Low mixing layer height is preventing efficient dispersion of pollutants.”
According to the India Meteorological Department (IMD) data, the Safdarjung Observatory, the base station for Delhi, the city received 0.8 mm rain over the past 24 hours. IMD scientists said that because of a Western Disturbance that had struck Delhi on Sunday resulting in light rain, cloud cover was there and both day and night temperatures were above normal.
“When there is a cloud cover and humidity in the atmosphere on its account, the temperature tends to increase. Also, the clouds and the moisture coupled with slow winds further allows the trapping of pollutants. Had the rain been moderate, it would have washed out pollutants, but it was too little to have any major impact on cleansing the air,” said a senior IMD scientist. He added that once the WD passes away, the minimum temperatures will gradually begin to drop.