Nearly 10,000 passengers were stranded at the Shuangliu International Airport in Chengdu, Sichuan Province, as thick fog forced the airport to close for four hours Friday. The airport was closed at 6:30 a.m. as visibility dropped to 40 meters due to the fog that began to spread in the city early Friday morning, said Lu Junming, an airport officer. Four domestic flights were cancelled and 113 others were delayed, leaving the passengers to wait for departure in airplanes or terminals, Xinhua reported. The airport authorities provided food and water to the stranded passengers. Among the delayed flights, 18 were heading abroad, including tourist destinations in southeast Asian nations. Affected flights gradually took off or landed after the airport resumed operation at 10:45 a.m. and most of the stranded passengers have got onboard as of 4 p.m., said Lu. The airport authorities had arranged 576 flights for Friday. The closure left 466 flights to postpone takeoff or landing and some have to fly overnight. But Saturday's schedule will not be affected, the airport authorities said. Meteorologists said dampness and sufficient sunlight jointly produced the fog weather.