Densest fog so far this winter in Delhi, flight operations severely hit

According to the Delhi Airport website, nine international flights and eight domestic flights flying out of Delhi and 11 flights flying into Delhi were delayed Monday morning.

The nine international flights heading from Delhi to Hong Kong, Paris, Newark, Sharjah, Bangkok, Dubai, Dhaka and Doha and eight domestic flights heading from Delhi to Ranchi, Patna, Mumbai, Bhubaneswar, Cochin, Ahmedabad and Port Blair were delayed on Monday, the site mentioned.

Additionally, 11 domestic flights arriving from Raipur, Guwahati, Jaisalmer, Mangalore, Chandigarh, Patna, Kolkata, Mumbai, and Cochin to Delhi, along with 11 international flights arriving from Melbourne, Dhaka, Phuket, Tokyo, Sydney, Sharjah, Hong Kong, San Francisco and Dubai to Delhi were delayed due to the fog conditions. One flight from Delhi to Jaipur was cancelled, the site mentioned.

The heavy fog resulted in seven flights flying into Delhi being diverted to Jaipur and one to Ahmedabad.

At Safdarjung, the city’s base weather station, visibility was better at around 200 m at 8.30 am. With ‘dense’ to ‘very dense’ fog expected on Tuesday and Wednesday as well, the IMD has issued an ‘orange’ alert for the city, which is a warning to be prepared. When visibility is less than 50m, the IMD categorises the fog cover as ‘very dense’, and visibility of 199 m to 50 m is categorised as ‘dense’ fog.

Till Monday, the national capital had seen visibility drop to a low of 50 m at Palam on December 2. Other parts of northwest India also recorded very dense fog on Monday, with visibility dropping to 0 metres at the airports at Amritsar, Agra, and Jaisalmer.

IMD scientist Kuldeep Srivastava said that the passing of a western disturbance helped bring moisture that aided fog formation. Additionally, winds over the city were light in the morning hours. “With faster winds, mixing takes place rapidly and fog will not form.

There are a few factors that came together to contribute to the very dense fog cover on Monday. The presence of a significant amount of moisture and clear skies helped – when the sky is clear, temperature tends to rise during the daytime, and in the early hours, the earth radiates this energy back to the atmosphere, contributing to the formation of fog,” he added.

Fog forms when water vapour condenses with temperatures dipping at night and in the early hours of the morning since colder air cannot hold as much moisture as warm air.

The minimum temperature early Monday morning was 7.8 degrees Celsius, close to the normal for this time of the year.
RK Jenamani, scientist, IMD, explained that local features at Palam may have contributed to the area having more moisture, and hence, denser fog than Safdarjung.

“Sometimes, there are local features that contribute to denser fog formation in some areas. Palam usually sees more fog hours than Safdarjung. In city areas, temperatures tend to be higher and moisture supply may be restricted because of concrete areas and roads,” he said.

While moderate to dense fog is expected on Thursday, shallow to moderate fog is likely on Friday, going by the IMD forecast. The minimum temperature is likely to remain at around 7 to 9 degrees over the next six days.

Total number of delayed flights on Monday

According to flightradar24 – an online portal that tracks flights around the world in real-time – 248 flights arriving in Delhi were delayed and 8 were cancelled, and 430 flights leaving Delhi were delayed and 21 were cancelled till Monday evening.

A total of 678 flights were delayed and 29 were cancelled.

Earlier this month, the Delhi International Airport Limited (DIAL) unveiled its fog preparedness strategy for the IGI Airport to ensure secure operations amid challenging reduced visibility conditions.