Delhi logs best AQI in 137 days on back of rain, gusty winds

Strong and gusty surface winds cruising at a speed of 40-50km/hour filtered out pollutants and aided the Capital in recording its cleanest day in terms of air quality in 137 days on Saturday, according to the India Meteorological Department.

According to the Central Pollution Control Board’s national bulletin, Delhi recorded a 24-hour average air quality index (AQI) reading of 117 (moderate) at 4pm, the lowest since October 17, 2023, when it read 89 (satisfactory).

Meanwhile, the prevalent cloud cover since Friday evening made the minimum temperature rise by a sharp 7.5 degrees and was recorded at 18 degrees Celsius (°C) — five degrees below normal. It was 10.8°C on Friday.

Officials from IMD said that the maximum temperature, on the other hand, went down by a couple of notches and was recorded at 25.2°C, two degrees below normal. The maximum was 29.6 degrees the day before. The cloud cover also makes it difficult for sunlight to reach the surface during the day scaling the maximum temperature down. Conversely, the cloud cover traps the heat at night, making the minimum rise.

Safdarjung, representative of Delhi’s weather, received 0.2 mm of rain in 24 hours till 8.30 am and 0.8 mm more during the day on Saturday. Other weather stations, including Ridge, Pusa and Pitampura, received 3.6mm, 2.5mm and 0.5mm of rain, respectively. Palam received about 2.5mm of rain throughout the day, IMD data showed.

“The rain is due to the influence of some western disturbances and the weather should start clearing up from Sunday. While some drizzle might be recorded in the early hours of Sunday, the sky will mostly be clear from Monday,” said a Met official.

IMD has forecast the minimum temperature to go down to 12°C by Monday while the maximum is forecast to stay around 25°C.

The Early Warning System for Delhi — an air quality forecasting model under the ministry of earth sciences — has forecast the AQI to be in the “moderate” category till Tuesday. “The air quality will likely be in moderate category from March 3 to March 5. The outlook for the subsequent six days is that the air quality is likely to be in the ‘moderate’ category,” said the EWS bulletin.

CPCB classifies an AQI between 0-50 as “good”, between 51 and 100 as “satisfactory”, between 101 and 200 as “moderate”, between 201 and 300 as “poor”, between 301 and 400 as “very poor” and over 400 as “severe”.