New Delhi: Dense smog hampered visibility at the Delhi airport this morning, affecting flight operations and leading to delays by up to two hours as only one of the three runways could be used.

Sources at the Indira Gandhi International Airport said that due to low visibility on the shorter runway 9/27, they could only use runway 10/28 in the morning.

The third runway 11/29 is shut from today for three days for maintenance.

The official added that the second runway was opened after visibility improved.

According to officials of the India Meteorological Department, runway visibility between 7am and 8am was less than 200 metres and improved around 11am.

“Due to air traffic congestion in Delhi, departure delays up to 90 minutes are expected at Delhi airport till 1500 hrs,” Jet Airways said in a tweet.

“Flights to and from Delhi may get delayed by up to 2 hrs due (to) runway closure for maintenance,” Vistara tweeted.

The smog has added to the woes of people flying in and out of Delhi as the airport is operating at 70 per cent of its capacity because of maintenance work on one of its runways.

The airport will be handling 800 flights per hour instead of 1,100 as airlines were told to curtail operations for three days. This means passengers will have fewer flight options to book as well as an increase in demand from travellers.