Aerial photo taken on Oct 19, 2017 shows Qinghai Lake, China's largest inland saltwater lake, in Northwest China's Qinghai province. The surface area of Qinghai Lake reached 4,497.01 square km, the highest record since 2001, according to data from the Qinghai Institute of Meteorological Sciences. Qinghai Lake plays an important role in the ecological security of the Qinghai-Tibet Plateau. It has been expanding since 2005 thanks to abundant precipitation in surrounding areas and increased snow melt due to climate change. [Photo/Xinhua]