While this January was the hottest in 46 years, data from the Indian Meteorological Department (IMD) shows that the month also witnessed one of the highest incidences of fog in nearly 20 years.
The IMD Wednesday said at least 15 cases of dense fog were recorded at Indira Gandhi International (IGI) Airport, spread over 429 hours covering almost all days of the month.
Data from December and January shows 750 hours of fog this season. After 2002-2003 which saw 758 hours and 2013-14 with 755 hours, this is the worst fog episode since 1996, said scientists.
New fog measuring and analysing instruments, set up in IGI this year by the IMD and IITM Pune, have shown fog accumulation was seen mostly at night and early morning when temperatures were low.
Dr R K Jenamani, head of IGI Met office in Delhi region, said, “In one particular episode, we saw low clouds and dense fog spells between January 13 and 24. During all these days, visibility was below 1,000 m. This was the fourth highest incidence of fog that Delhi has seen in January in recent years.”
The project, chaired by Prof G S Bhatt from Indian Institute of Science and jointly conducted by IITM and IMD, set out to understand scientific aspects of the winter fog formation in Delhi. However, scientists said December barely had any episodes of fog.