Air operations at the Indira Gandhi International airport here virtually come to a standstill on Monday morning due to dense fog which disrupted the schedule of over 20 flights and led to the diversion of two others.

A Jet Airways flight from Abu Dhabi was diverted to Mumbai while a Spicejet flight from Mumbai was diverted to Jaipur after general visibility dropped to less than 50 metres, an airport official said.

Most of flights scheduled to depart early morning were delayed as the runway visibility dropped to 75 metres, far below the required minima of 125 metres.

Fog started to become dense around 3 a.m. forcing the authorities to implement low visibility procedures on third runway at 3.32 a.m.

Visibility at the main runway also started to deteriorate around 5.30 a.m. and authorities implemented the low visibility procedures at 5.45 a.m.

The visibility hovered between 75 to 100 metres due to which no take offs were possible resulting in delay of over 20 flights, the official said.