Flight services in Bagdogra airport got disrupted for around six hours on Tuesday as dense fog brought down the visibility of the airport.

The disruption, which inconvenienced hundreds of passengers, has again raised the demand to resume the instrumental landing system (ILS) at the airport.

In Bagdogra, the runway and air traffic control are maintained by the Indian Air Force (IAF). A few years back, ILS was installed at the airport to ensure flight landing even in low visibility.

“However, for the past two-and-a-half years, ILS is not used in Bagdogra as re-carpeting of the runway and some other infrastructure enhancement work are in progress. That is why flights need higher visibility to land. As there was fog today, visibility came down. A number of flights with Bagdogra as the destination had to be diverted to other destinations while some others didn’t take off from different airports,” said a source from the Airports Authority of India (AAI).

According to him, if ILS is operational, a flight can land with a visibility of 800 or 850 metres. Without ILS, there should be visibility of around 1,600 metres.

On Tuesday morning, as hundreds of passengers reached the airport, they did not know when their flights would arrive. As the day rolled on, more people poured in, causing congestion at the terminal building. The AAI arranged for extra seats.

In the afternoon, as the sun came up and the visibility increased, flights started landing and taking off.

“We are aware that there can be inconveniences in winters and monsoons if ILS is not used at the airport. The AAI and the airline companies have communicated with IAF and we believe they are putting in their best effort to finish the work soon,” the source added.

AAI sources later said there were 40 flight movements while eight were cancelled and 6,778 passengers travelled on Tuesday.

Usually, around 50 flight movements are recorded in Bagdogra and 8,000-odd passengers use the airport.