It is the same story every year. As dense fog envelopes the Indira Gandhi International Airport, hundreds of passengers are stranded with flights being delayed for hours.
This is when every year airlines and civil aviation authorities make claims that there are enough CAT III-B trained pilots to ensure flight operations even in near zero visibility.
The truth, however, is that only Air India and international flights operate during the worst spells of fog while flights of other airlines wait for the weather to improve.
Last winter, Air India operated the largest number of flights during dense fog followed by Kingfisher and IndiGo, which operated far fewer flights than the national carrier.
"With two runways, the airport can easily handle up to 40 flight movements per hour even when visibility is below 200 metres. Very few pilots, however, are willing to operate in such conditions," said a senior airport official on condition of anonymity.
"We end up handling only 15 flights per hour that can be operated from just one runway. That means that the new runway, which witnesses much less visibility than the main one, is not used at all," he said.
As per the data of private airport operator Delhi International Airport Ltd, the largest number of flights during fog are operated during CAT I conditions, when visibility is up to 550 metres. As visibility starts dropping to CAT II and CAT III-A and B conditions, the number of flights also dry up.