New Delhi: The first spell of dense fog in 2012 wreaked havoc on air operations at the IGI airport on Wednesday hitting over 250 flights and causing inconvenience to flyers.
At least 207 domestic and international flights were delayed by five to six hours as the runway visibility remained below the prescribed minima for low visibility take-off of 125 and 150 metres for different types of aircraft.
Four flights, two each of Jet Airways and SpiceJet, were diverted to Jaipur, Ahmedabad and Indore while 17 flights were cancelled, an airport official said.
Though the airport was witnessing shallow fog since 8:30 pm on Tuesday night, the flight operations were not affected.
But the situation started to deteriorate after 1:40 am, when blinding fog enveloped the airport, reducing the runway visibility to less than 100 metres.
The situation remained same around 10 am, when the fog dissipated and visibility increased.
Virtually there was no flight operation between 1:40 am and 9:40 am as the runway visibility hovered between 75 and 100 metres for new runway (29/11) and between 100 to 125 for main runway (28/10), below the prescribed norm.
However, flights arriving here were able to land using the CAT-III B instrument landing system (ILS).
The fog was so dense that the general visibility also dipped to less than 50 metre, an airport official said, adding the low visibility procedure was implemented on main runway at 1:46 am and on new runway from 3:45 am. It was terminated at around 11:20 am.