Farmers harvest salt in Mangkam County of Qamdo, Tibet

This photo taken on March 11, 2018 shows saline fields in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields. (Xinhua/Jigme Dorgi)

A salt farmer examines saline stalactites formed by trickling brines in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region, March 11, 2018. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields.(Xinhua/Jigme Dorgi)

This photo taken on March 11, 2018 shows saline fields and stalactites in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields until the salt. (Xinhua/Jigme Dorgi)

A salt farmer works among patches of saline fields in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region, March 11, 2018. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields. (Xinhua/Jigme Dorgi)

A salt farmer works among saline fields in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region, March 11, 2018. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields. (Xinhua/Jigme Dorgi)

A salt farmer works among patches of saline fields in Mangkam County of Qamdo, southwest China's Tibet Autonomous Region, March 11, 2018. Local salt farmers have followed a centuries-old harvesting method by collecting brines from the rocks and drying them in prepared fields. (Xinhua/Jigme Dorgi)