Weather department officials said high moisture content in the air and a significant difference between the daytime and nighttime temperatures create conditions that are favourable for the formation of fog.
Delhi experienced an unusual spell of shallow fog on Thursday morning, leaving residents surprised. Such weather conditions are not typical for May which is the hottest month of the year in the city with a mean maximum temperature of 39.5 degrees Celsius.
Weather department officials said high moisture content in the air and a significant difference between the daytime and nighttime temperatures create conditions that are favourable for the formation of fog.
According to the IMD, shallow fog is when visibility is between 501 and 1,000 metres. The Safdarjung Observatory, Delhi's primary weather station, recorded 20.9 mm of rainfall between 8.30 am and 5.30 pm on Wednesday, and a maximum temperature of 30.6 degrees Celsius, nine notches below normal.
The city logged a minimum temperature of 16.9 degrees Celsius at 6 am on Thursday. Palam, Lodhi Road, Ridge, Ayanagar, Mungeshpur, Narela, Pitampura and Pusa logged 11.8 mm, 24.6 mm, 14.6 mm, 13.8 mm, 31.5 mm, 9.5 mm, 55.5 mm and 15.5 mm of precipitation, respectively, on Wednesday.