Photo taken on Dec 21, 2017 shows the frozen Qinghai Lake, China’s largest inland lake and biggest saltwater lake, in Northwest China’s Qinghai province. [Photo/Xinhua]

Photo taken on Dec 21, 2017 shows the sunset glow over the frozen Qinghai Lake, China’s largest inland lake and biggest saltwater lake, in Northwest China’s Qinghai province. [Photo/Xinhua]

Photo taken on Dec 21, 2017 shows the frozen Qinghai Lake, China’s largest inland lake and biggest saltwater lake, in Northwest China’s Qinghai province. [Photo/Xinhua]

Photo taken on Dec 21, 2017 shows the frozen Qinghai Lake, China’s largest inland lake and biggest saltwater lake, in Northwest China’s Qinghai province. [Photo/Xinhua]