Delhi experienced a prolonged spell of dense fog on Saturday, with zero visibility for almost nine hours, marking the longest fog-related disruption of the season, according to the weather department.

“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,” the weather body stated.

400 flights delayed, 81 trains affected due to dense fog

A total of 81 trains were delayed, with some running up to eight hours behind schedule, as the severe fog led to significant disruptions in flights and trains.

On Saturday, IGIA recorded 19 flight diversions between 12:15 am and 1:30 am, including 13 domestic, four international, and two non-scheduled flights.

An official confirmed that over 45 flights were cancelled due to poor weather in Delhi and at other destination airports while a total of more than 400 flights faced delays on Saturday.

Despite these conditions, flights compliant with CAT III, which allows for operation in low-visibility conditions, continued to land and take off.

Delhi AQI in the last 24 hours

The dense fog also contributed to poor air quality, with Delhi’s 24-hour average Air Quality Index (AQI) recorded at a concerning 378, placing the capital 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’.

Meanwhile, large parts of Punjab and Haryana have been experiencing thick fog for the past few days and on Saturday, visibility dropped to zero at many places including Amritsar, Ludhiana, Patiala, Ambala, Hisar and Karnal, while Chandigarh was also blanketed by heavy fog in the morning hours.