Buildings are enveloped in sandstorm in Kax, a city in northwest China's Xinjiang Uygur Autonomous Region, on Sept. 5, 2010. A heavy sandstorm hit Kax on Sunday, lowering the visibility to less than 100 meters in the city.

People drive motorcycles in sandstorm on a street in Kax, a city in northwest China's Xinjiang Uygur Autonomous Region, on Sept. 5, 2010.