Aerial photo taken on Aug. 9, 2019 shows the view of Qumar River at the headstream region of Yangtze River, China's longest river, in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 6, 2019 shows the view of Damqu River at the headstream region of Yangtze River, China's longest river, in Zadoi County, Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Qumar River at the headstream region of Yangtze River, China's longest river, in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Tuotuo River at the headstream region of Yangtze River, China's longest river, in Tanggulashan Township of Golmud City, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Tuotuo River at the headstream region of Yangtze River, China's longest river, in Tanggulashan Township of Golmud City, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Tuotuo River at the headstream region of Yangtze River, China's longest river, in Tanggulashan Township of Golmud City, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Qumar River at the headstream region of Yangtze River, China's longest river, in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province. (Xinhua/Wu Gang)

　　Aerial photo taken on Aug. 9, 2019 shows the view of Tuotuo River at the headstream region of Yangtze River, China's longest river, in Tanggulashan Township of Golmud City, northwest China's Qinghai Province. (Xinhua/Wu Gang)