Delhi sees season’s first dense fog episode, ops hit at IGI airport

Delhi International Airport Limited said on X that low visibility procedures were initiated at the airport. “While landing and takeoffs continue at Delhi Airport, flights that are not CAT III compliant may get affected,” it said.

The IMD classifies fog as ‘shallow’ when the visibility falls between 500 m and 1,000 m, and ‘moderate’ when it is up to 200 m. ‘Dense’ fog is reported when the visibility is reported up to 50 m; further low visibility levels indicate ‘very dense’ fog. According to the IMD, shallow fog prevailed in Delhi-NCR on Wednesday evening.

The IMD has issued an orange alert for Thursday (November 14) and a yellow alert for Friday due to the intensification of fog conditions. Dense to very dense fog is forecast for Thursday and moderate to dense for Friday.

It has forecast moderate fog or smog conditions in the morning, with smog or mist likely in the evening, from Saturday (November 16) to November 19.

Dense fog and cloud cover conditions are forecast to prevail over northwest India due to the influence of surface-level westerlies, IMD officials said.

A fresh western disturbance prevails over the Northwest, said the IMD. The weather phenomenon, which refers to storms that originate in the Mediterranean Sea, brings moisture-bearing winds to Northwest India and are driven by Westerlies.

A view of the India Gate in New Delhi on a foggy Wednesday morning. (Express Photo by Tashi Tobgyal)

“Over Delhi, the weather has significantly changed with respect to the intensification of fog conditions in the morning… with fog or smog coverage staying a longer part of the day, sunlight cut off may cause fall of maximum temperature,” IMD scientist R K Jenamani said.

Due to lower visibility throughout the day and very dense fog in the morning, maximum temperatures fell over Delhi (Sardarjung) from 32.8 degrees Celsius on Tuesday to 27.8 degrees Celsius on Wednesday. The minimum temperature was 17 degrees Celsius on Wednesday which is still 3.5 degrees above the season’s normal. However, it was a drop from the previous day’s minimum temperature reported at 17.9 degrees.

“The mainly smog condition with wind speed less than 10 kmph from northwest directions prevailed over the region in the forenoon today,” the IMD said on Wednesday.

Meanwhile, the most polluted region was Aya Nagar with AQI 428 followed by Anand Vihar station at 413 AQI, both in the ‘severe’ category according to IMD.

The Indian Institute of Tropical Meteorology (IITM), in its extended range forecast, has forecast the meteorological conditions to remain highly unfavourable for the dispersal of pollutants.

The IMD also said the predominant surface wind blowing from the Northwest or Southwest direction with speed reaching 4 to 8 kmph prevailed during the past 24 hours. The low wind speed is unfavourable for the dispersal of pollutants.

Visibility in other airports across Northwest India

According to the Met Office, ‘moderate’ fog conditions were observed at the airports of Chandigarh, Hindon (Ghaziabad), Bhisiana (Punjab), Ambala (Haryana) and Sarsawa (Uttar Pradesh) as of 9.30 am.

While a dense layer of fog prevailed at Amritsar and Halwara airports with visibility of 50 m and 100 m respectively, in other airports in the northwest region such as Agra, Kushinagar, Gorakhpur, Ayodhya, Varanasi, Bikaner, Deoghar and Bhopal the fog was reported to be shallow.