Heavy fog has continued shrouding Urumqi, capital city of northwest China's Xinjiang Uygur Autonomous Region, for the second day on Sunday, stranding about 10,000 passengers at the city's airport as more flights were delayed or cancelled.

Sunday's fog had not dispersed until about 4 p.m., delaying a total of 398 inbound and outbound flights scheduled for the day, airport authorities said.

It would take about 30 hours to resume all the delayed flights after the fog dispersed, according to the airport authorities.

Saturday's fog that last about 13 hours from early morning had disrupted 258 inbound and outbound flights, causing delays and cancellations.

The airport had resumed normal operation for only about one and half an hour by late Saturday afternoon, giving chances for 22 flights to take off or land.

The heavy fog was a result of high humidity amid cold weather, according to the meteorological department of the airport.