Dense fog in Delhi, city sees season's longest zero visibility spell

Dense fog enveloped the national capital on Saturday, reducing visibility to zero for an unprecedented nine-hour stretch, the longest spell of the season, according to the weather department.

The dense fog led to the delay of 81 trains while 15 flights got diverted on Saturday, according to officials. 

"Zero visibility prevailed for nine hours at Palam between 6 pm and 3 am (UTC), marking the longest spell of the season.

The city's primary weather station, Safdarjung, recorded eight hours of zero visibility, as per the IMD."  With the the maximum temperature in the city settled at 20 degrees Celsius, 0.7 notch above average and the minimum temperature was recorded at 7.8 degrees Celsius, 0.9 notch above the normal, according to the India Meteorological Department (IMD) said.

 

The relative humidity during the day ranged between 96 and 100 per cent, it said.

For Sunday, the weather department has predicted a partly cloudy sky. The predominant surface wind is expected to blow from the southeast at a speed of less than 4 kmph during the morning hours.

Smog and moderate fog are likely in most areas, with dense fog expected in a few places during the morning. The wind speed is forecast to gradually increase to 8-10 kmph from the southeast in the afternoon, before decreasing to less than 6 kmph in the evening and night.

Smog or shallow to moderate fog is likely during the evening and night, it said.

The maximum and minimum temperatures are expected to settle around 18 and 10 degree C, respectively.

At 7 am, general visibility at the Indira Gandhi International Airport was zero in very dense fog. The Runway Visual Range (RVR) at its runways was in the range of 100-250 metres, with CAT III conditions.

Such very dense fog in zero visibility with CAT III conditions at the airport has been prevailing since 11:30 pm on Friday, the Met office said.

"While landing and takeoffs continue at Delhi airport, flights that are not CAT III compliant may get affected. Passengers are requested to contact the airline concerned for updated flight information. Any inconvenience caused is deeply regretted," the Delhi International Airport Limited, which operates the airport, said in a post on X at 6. 56 am.

CAT III facility allows aircraft to operate in low-visibility conditions.

The Northern Railway said a total of 59 trains were running late by up to six hours and 22 by around eight hours.

In a related development, the air quality in the national capital remained in the 'very poor' category.

Delhi's 24-hour average AQI was recorded at 378, according to data from the Central Pollution Control Board (CPCB).

An AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.