Aerial photo taken on April 21, 2018 shows workers planting trees on the Kubuqi Desert in North China's Inner Mongolia autonomous region. Thousands of workers devote themselves into the desertification control of Kubuqi Desert in April and May every year, during which they live on the desert, plant trees and set obstacles to fix the sand. By far, 25 percent of the Kubuqi Desert has gotten rid of desertification. [Photo/Xinhua]

A worker plants trees on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 21, 2018.[Photo/Xinhua]

Workers plant trees on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 21, 2018.[Photo/Xinhua]

Workers plant trees on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 21, 2018.[Photo/Xinhua]

A worker plants trees on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 21, 2018.[Photo/Xinhua]

A chef prepares lunch for workers outside a tent on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 18, 2018.[Photo/Xinhua]

Workers have lunch inside a tent on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 18, 2018.[Photo/Xinhua]

A worker carries tree seedlings on the Kubuqi Desert in North China's Inner Mongolia autonomous region, April 21, 2018.[Photo/Xinhua]