Dense fog played havoc with flight operations at the Delhi airport on Monday with around 530 flights delayed, 40 cancelled and 21 diverted.
Flights are operating at the airport under CAT III B conditions, which means the runway visual range (RVR) is between 50 metres and 175 metres.
Giving an update on flight operations, an official said 21 flights have been diverted and around 40 cancelled as of now.
"Around 530 flights - which includes 320 departures as well as 210 arrivals approximately - have been delayed on Monday," the official added.
In a statement, IndiGo airline said,"Owing to dense fog in north India our flights have been impacted across India. We will continue to review the situation and provide real time updates on our social platforms."
The airline also requested passengers to check flight status before leaving home and reach out to its customer care.
Vistara airline said on Twitter that its Delhi-Mumbai flight UK933 as well as Mumbai-Delhi flight UK996 stands cancelled due to poor visibility in Delhi.
Vistara along with GoAir, SpiceJet, AirAsia India stated on Twitter that due to dense fog and poor visibility in Delhi, their flight operations might be impacted, and advised passengers to check flight status before leaving for the airport.
Delhi, which is shivering under an intense spell of cold wave for two weeks, experienced its coldest recorded December day on Monday.