Flight schedules were affected at Chennai airport on Friday following fog in Delhi.
Four departures and three arrivals were delayed after schedules were affected at other airports due to disruptions in Delhi.
Three flights from Mumbai were delayed by half an hour to two hours while four departures, including a flight to Delhi, were delayed by one hour to two hours between 6am and 10.30am.
A Jet Airways flight to Mumbai left at 9.30am instead of its schedule time of 8am. An Air India Delhi flight was delayed by 30 minutes, while another Air India flight to Bangalore, scheduled for 6am, departed only at 9.30am.
An Air India flight from Mumbai, that was to arrive here at 9am, was delayed by more two and a half hours.
Airport officials said the flights were getting delayed because aircraft got stuck at Delhi airport due to congestion created by fog. "The same aircraft is used to fly on different routes. If there is a delay at one airport, it will have an impact on the schedules elsewhere," said an official.
Airlines have tweaked their departures to minimise delays. "The situation in Delhi has improved. We do not expect further delays in Chennai," said an airline official.
Seven departures were cancelled and eight flights were delayed in Delhi on Friday morning.