Villagers work at a nursery base in Zhanang County of Shannan, southwest China's Tibet Autonomous Region, July 23, 2018. Over the past four decades, the Shannan people have made achievements in desert control by building a 1.8-kilometer-wide "green Great Wall" that stretches 160 kilometers. More than 30,000 hectares of desert land in the middle reaches of Yarlung Zangbo River has been reclaimed. (Xinhua/Liu Dongjun)