Chengdu's Shuangliu International Airport in the capital of southwest Sichuan Province was closed for six and a half hours on Dec. 16 by fog, delaying hundreds of flights and stranding more than 10,000 passengers.

The airport closed at 4:30 a.m. when the fog, the heaviest so far this year, developed.

"The visibility was then only about eight meters, far below the minimum of 500 meters for planes to take off," said airport spokesman Lu Junming.

Lu said 416 incoming and outgoing flights were scheduled on Dec. 16 and most would be delayed for at least three hours.

The fog had dispersed by noon, although service began to be restored about an hour earlier when a flight to Shenzhen in Guangdong Province took off and a flight from Taiyuan, Shanxi Province, landed.

Airport authorities said they expected more fog on Dec. 17 because of humid conditions.

The Shuangliu airport is one of the busiest hubs and distribution centers for passengers and cargo in southwest China.