New Delhi: Six flights were cancelled and over 60 delayed due to fog at the Indira Gandhi International Airport here this morning.

Nearly 40 domestic and 26 international flights were among those delayed.

According to the Indian Meteorological department, general visibility improved to 200 metres at IGI as compared to zero metres the past two days.

The runway visual range (RVR) was between 800-1000 metres early this morning. This is also an improvement, as RVR was in the range of 50-100 metres in the last two days.

Take-offs at IGI require a minimum RVR of 125 metres and landings can take place with a minimum RVR of 50 metres.

"Operations this morning are normal thus far as visibility at DEL is within minimums, but may change at short notice," Vistara airline informed passengers on Twitter.

The airline is also allowing passengers to change or cancel their flight bookings without any penalty.

Trains were also hit today due to fog. 64 trains were delayed and 21 cancelled while 24 were rescheduled, according the spokesperson for the Northern Railways.