New Delhi: Over 90 flights were affected this morning as visibility dropped to 50 metres due to dense fog at the Indira Gandhi International Airport here, the heaviest this year.

While 54 domestic flights were delayed and 17 diverted to other airports, eleven international flights were delayed and 8 were diverted due to the dense fog, according to flight information available on the airport's website.

So far there have been 4 cancellations, including three domestic and one international flight, according to the information.

RK Jenamani, Director, IMD, Delhi area and IGI airport said, "Runway visibility since 5.30 am has been between 50-75 metres. This is so far the worst fog we have experienced this year." 

Delhi airport has advanced technology for low-visibility landings, called CAT IIIB. As a result landings can take place with a visibility of 50 metres. However, for take-offs a minimum visibility of 125 metres is required.