Delhi records zero visibility for fourth day in a row

Officials at Delhi’s Indira Gandhi International (IGI) Airport said no flight was diverted or cancelled on Sunday, but several were delayed

Delhi logged zero visibility for a fourth consecutive day on Sunday, for over three hours between 4am and 7.30am this time, impacting flight and train operations. The fog spell, however, was shorter-lived than the nine hours of zero visibility clocked a day before.

A view of Leisure Valley Park in Gurugram on Sunday morning. (Parveen Kumar/HT Photo)

Officials at Delhi’s Indira Gandhi International (IGI) Airport said no flight was diverted or cancelled on Sunday, but several were delayed. According to the flight tracking website Flightradar24, over 300 flights were delayed at the airport. The website also showed 18 cancellations, but it did not specify whether this was due to adverse weather or other reasons.

“No cancellations or diversions were reported on account of fog on Sunday. On Saturday, 19 flights had to be diverted and over 40 were cancelled,” an official at the airport said.

The India Meteorological Department (IMD) said visibility was zero at the Palam observatory for three hours, while it was 50 metres at the Safdarjung observatory at 5.30am, making the early morning commute difficult. IMD issued a yellow alert for Monday, forecasting moderate fog in most places and dense fog in isolated pockets.

People took to social media, questioning airlines over delayed arrivals and departures from Delhi.

Arman, a passenger, posted on X: “Flight 6E-2083 which was scheduled to depart from Varanasi to Delhi this morning was delayed for almost 3 hours. Which will result in me missing my connecting flight from Delhi to Dehradun. What if I miss my connecting flight ? I urgently need to reach Dehradun today (sic).”

The airline, IndiGo, responded by saying the delay had occurred on account of bad weather. “We regret this discomfort and assure you that it is never our intent to disrupt the travel plans of our flyers. However, your flight was affected due to the consequential effect of bad weather affecting our arriving aircraft, which is beyond our control...” the airline posted on X.

Trains, too, were impacted in the early hours of the day. Northern Railways said 51 trains were delayed by over 30 minutes in the region.

On Saturday, the season’s worst fog spell in terms of intensity, visibility remained zero for nine hours between 11.30pm on Friday and 8.30am on Saturday. This had a cascading effect at the airport, with delays and cancellations being reported even after the sun had come out.

IMD classifies fog as “shallow” when visibility is between 500 and 1000 metres; “moderate” when it is between 200 and 500 metres; “dense” when it is between 50 and 200 metres and “very dense” when it is below 50 metres.

Mahesh Palawat, vice president at Skymet, said the intensity of the fog is expected to reduce marginally on Monday, with the possibility of some rain. “We are likely to see some cloudiness and subsequent rain,” he said.

For fog to be “very dense”, Palawat said winds need to be calm, with skies to be clear and moisture content to be high.

RK Jenamani, a scientist at IMD, meanwhile, said fog conditions on Sunday were far better than Saturday as Delhi was helped by a “fog hole” forming over the city. This generally occurs due to factors such as the urban heat island effect, where concrete and urbanisation lead to areas recording higher temperatures than surrounding green areas.

“The fog lifted early on Sunday through the activation of an urban fog hole. This was due to local factors and heating which was specific to Delhi-NCR. If one viewed satellite imagery, a thick layer of fog was still visible across the Indo-Gangetic Plains, even when the fog over Delhi had lifted,” said Jenamani, adding moderate to dense fog was likely on Monday too.