Out of these total flights, 10 were cancelled either due to bad weather or operational reasons. An Air India international flight was diverted to Mumbai, an airport official said.

Dense fog started to descend at the airport around 10 PM last night but it thickened between 1 AM and 5:30 AM leading to drop in runway visibility to less than 25 m at the third runway, forcing officials to suspend operations on the strip.

Though dense fog enveloped the airport, operations largely remained normal as the main runway was operational through the night as the runway visibility was above the permissible limit of 150 m for takeoff, the official said.

The main runaway is equipped with CAT-IIIB Instrument Landing System (ILS) at both ends so it can facilitate landing of aircraft even if runway visibility is upto 50 m, he said.

The poor visibility led to implementation of low visibility procedures and a total of 137 flights operated using various categories of ILS.

Airport has been witnessing fog for past three days affecting the schedule of over 250 flights.

Dense fog had yesterday also played spoilsport for the fliers on New Year day as it disrupted operations at the airport, affecting over 100 flights.