The casualty: over 150 flights delayed, 30 cancelled, and 27 rescheduled.

On Saturday, dense fog had begun gathering by 9 pm, the weatherman said. Sunday is expected to be the worst so far this season so far as fog is concerned, the Met department said.

And as the wait for passengers grew longer, the Delhi International Airport Limited’s (DIAL) pride — CAT-III B-enabled third runway 29-11 — remained inactive for a major part during the fog. This was the third consecutive day that the new runway, said to be the most improvised runway in the advent of fog, remained ineffective during fog.

Runway 29-11 could not be used till 9 am on Saturday, and for more than 11 hours runway 28-10 handled all air traffic alone — for both arrival and departure. Low visibility procedures (LVP) were enforced at 10.30 pm Friday, when visibility began dipping.

Passengers, as has become the norm at the city airport during such times, had a nightmare almost all day, waiting for flights, or for their friends and relatives arriving in held-up flights. “I had to go to Kolkata for an urgent meeting but my early-morning flight was delayed by three hours. I don’t know whether it will take off today,” P K Basu said, waiting at the airport.

Basu said he had not received any information about the flight delay when he left home, amid a blinding fog, at 5 on Saturday morning.

Incoming passengers had it equally bad, cooped up inside aircraft, often for hours. “My flight was supposed to leave Chennai for Delhi at 6.35 am, and I reached the Chennai airport an hour earlier to be safe,” said Rahul Mehra, who eventually landed in Delhi at 12.30 pm. “No information was given to us besides half-hourly announcements about further delays.

“Finally, after we boarded in Chennai, we had to wait in the aircraft for a couple of hours.”

Some of the international flights, which generally operate during night from IGI Airport, also got delayed due to the fog. In all, 10 flights, including three international flights, were diverted to Mumbai.

A total of 177 flights — including 55 domestic arrivals, 63 domestic departures, 35 international arrivals, and 24 international departures — operated during low-visibility conditions. Only 39 flights operated in CAT-III conditions.

According to airport officials, the low-visibility conditions continued for 13 hours and 41 minutes. The fog started setting in at the airport around 8.30 pm Friday and stayed till 3 pm Saturday. Visibility dropped to zero and runway visibility hovered around 75 metres to 200 metres between 1.30 am and 9 am Saturday.

Patna, Amritsar and Varanasi airports, besides several others in the region, were also reeling under similar weather conditions, it was informed.

“The last time we observed such bad weather affecting the entire country’s aviation was in January 2003,” said R K Jenamani, director, IGI Meteorological department.