On Friday, the India Meteorological Department officially announced the departure of the southwest monsoon from Delhi, a 13-day delay from the usual withdrawal date of September 25. Colder northwest winds are predicted in the coming days, resulting in a reduction in night time temperatures but a worsening in air quality. On Friday, the total AQI had already begun to rise over the moderate level, with two stations in Delhi recording 'very bad' air quality in the morning.Since 2015, it has not been unusual for a withdrawal to be delayed. The monsoon ended on October 10 in 2019, and on October 8 in 2016. In reality, the typical date of monsoon withdrawal from Delhi was somewhere around September 21 to four days later based on data from the previous three decades.This year, between June 1 and September 30, Delhi got 1,169.7 inches mm of rainfall, compared to the average 648.9 mm which is an increase of 80 percent. To put this in context, the city received 404.3 mm of rainfall in the 2019 season, compared to 576.6 mm the previous year. With an extra 3.4 mm of rainfall in October, 2021 was the third wettest season for Delhi.
"The southwest monsoon has withdrawn from some more parts of Gujarat, most parts of Rajasthan, the complete Punjab, Haryana, Chandigarh and Delhi, Jammu and Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, and some more parts of Uttar Pradesh and Madhya Pradesh today," according to an IMD bulletin issued on Friday.
According to a MET official, the withdrawal has caused changes in weather conditions, including wind direction, with colder winds predicted to come from the northwest. While the days may be pleasant, night temperatures are expected to drop by 2-3 degrees Celsius during the following seven days.Air quality will deteriorate significantly, with the total 24-hour AQI rising to 167 on Friday from 127 on Thursday. The two stations in Dwarka and Anand Vihar recorded AQIs of above 300 in the morning, putting the air in the 'very bad' category. The AQI for the Shadipur station was 206 (poor).
A government forecast organisation, the System of Air Quality and Weather Forecasting and Research, anticipated deterioration in air quality over the following three days due to a combination of cooler air and paddy burning in northwest India. The air quality in Delhi would be moderate to poor for the next three days, according to the forecast.