File photo taken on April in 2002 shows local villagers' houses surrounded by sand dunes at Liming Village of Maerzhuang Township in Yanchi County, northwest China's Ningxia Hui Autonomous Region. Located on the southern edge of the Maowusu Desert, Yanchi County was once poverty-stricken and suffered from desertification. But after years of efforts, the environment there has been restored, and the county has also shaken off poverty. (Xinhua/Liu Quanlong)