Thousands of travelers were left waiting for hours on end by the thick fog that disrupted aircraft and rail operations in the Capital for about 11 hours on Sunday, according to airport and railway officials. At 12.30 am, visibility fell to 200 meters, and it was completely absent for about seven and a half hours between 3 am and 10.30 am. As a result, approximately 400 planes were delayed, 10 were diverted, and at least 20 were canceled, according to airport officials.
Despite five hours of enhanced visibility due to sunlight, from 12 p.m. to 5 p.m., the cascading impact of delays persisted until dusk. The ten diversions to the Jaipur airport were due to low visibility, and this was also the biggest fog period of the year that affected transit operations. “A total of 10 flights were diverted at the airport. This occurred at different times between 4.30 am and noon,” said an airport official.
The Delhi airport's website indicated that roughly 200 aircraft were delayed during the day, despite the lack of official confirmation of the exact number of delayed flights. Also, the website displayed a minimum of ten cancellations. The airport initiates low visibility procedures (LVP) – measures aimed at making landing for flights easier — when visibility goes below 800 metres. CAT-I procedures—the simplest set of safety measures to help pilots land—are in effect during this time. When visibility is less than 550 meters, landings are only permitted by aircraft and pilots that comply with CAT-II standards. In addition, when visibility is between 175 and 300 meters, CAT-IIIA pilots are permitted to land. The strictest rating, CAT-III B, permits them to land even in situations with less than 50 meters of sight.
Flight delays result from the fact that no aircraft is permitted to take off until the runway visibility range (RVR) reaches 125 meters, even though aircraft may still land at the airport with 50 meters of visibility. Due to planes still in line to land at the airport and occupied parking bays, this may cause further delays.
The ongoing maintenance on one of the runways also caused difficulties for flight operations. As of August 2023, the airport has three of its four runways in use, and for the past four months, renovations have been made to runway 28/10. Two out of the three runways are capable of handling landings and takeoffs in CAT 3. When an airline's pilot does not comply with CAT 3, there are instances where aircraft are also diverted.
