Light rain helps pull down pollution, AQI moderate

NEW DELHI A day after the light rain on Thursday, when the minimum temperature in the city had climbed to 12.4 degrees Celsius, the mercury dropped once again on Friday to a minimum of 6.8 degrees Celsius — two degrees below season’s normal.

India Meteorological Department (IMD) scientists said the drop was primarily due to the cold, dry winds blowing in from the snow-clad western Himalayas.

The Safdarjung observatory, which provides the representative data for the city, recorded a minimum of 6.8 degrees Celsius, two notches below normal, on Friday as against 12.4 degrees Celsius on Thursday. The maximum temperature was 23 degrees Celsius.

Kuldeep Srivastava, head of IMD’S regional weather forecasting centre, said with the passing of the western disturbance, the wind direction over Delhi has changed to northwesterly.

“Cold, dry winds from the mountains have started blowing over the plains, resulting in a dip in the minimum temperature,” an IMD official said.

He said the temperature is likely to fall further over the weekend and settle at around 5-6 degrees Celsius. However, by February 8, the temperature will rise again.

“There is another western disturbance that is likely to impact the Himalayas. Its impact on the plains will be a slight rise in the minimum and maximum temperature,” Srivastava said.

Meanwhile, the light rain on Thursday, coupled with strong winds, improved the city’s air quality significantly. The Central Pollution Control Board (CPCB) recordings show that the overall air quality index (AQI) in Delhi on Friday was 133, in the ”moderate” zone. On Thursday, the average AQI was 316, in the ”very poor” category.

Union ministry of earth science’s air quality monitoring centre, System of Air Quality and Weather Forecasting and Research (Safar), said isolated rain observed under the influence of a western disturbance and high winds contributed to the improvement in AQI.