Birds fly over the Hulun Lake in Hulun Buir, north China's Inner Mongolia Autonomous Region, Aug. 28, 2019. Located in the hinterland of the Hulun Buir Grasslands, Hulun Lake is the fourth largest freshwater lake in China. Over the past few years, Hulun Lake has made great progress in wetlands restoration and biodiversity improvement. (Xinhua/Chen Jianli)