Passengers wait for taxis at the International Airport in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region, March 12, 2010. Several flights were delayed because of the heavy fog that enveloped the city on Friday morning and some 1,300 passengers were held up at the airport.

A young woman carrying a baby on her back waits for her flight at the International Airport in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region, March 12, 2010. Several flights were delayed because of the heavy fog that enveloped the city on Friday morning and some 1,300 passengers were held up at the airport.

Passengers wait for their flight at the International Airport in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region, March 12, 2010. Several flights were delayed because of the heavy fog that enveloped the city on Friday morning and some 1,300 passengers were held up at the airport.