Members of a Chinese scientific expedition team mark the sediment core of Lake Yamzhog Yumco in Nanggarze County of Shannan, southwest China's Tibet Autonomous Region, July 22, 2019. Chinese scientists are working on a survey to measure the depth of a major lake in southwest China's Tibet Autonomous Region, sources with the Chinese Academy of Sciences (CAS) said Tuesday. Lake Yamzhog Yumco with an area of about 590 square km is located in Nanggarze County in the city of Shannan. Yamzhog Yumco along with Lake Namtso and Lake Manasarovar are regarded as the three holy lakes of Tibet. (Xinhua/Jigme Dorje)