Staff members work at a 110 kV power transmission station in Tsonyi County, Nagqu City, southwest China's Tibet Autonomous Region, Dec. 24, 2019. The world's highest county, Tsonyi, Nagqu City, southwest China's Tibet Autonomous Region, was connected to China's state grid Tuesday, enabling a stable power supply for more than 7,000 local residents. In the county seat with an altitude of more than 5,000 meters above sea level, power workers braved a coldness of minus 20 degrees Celsius to start the equipment on Tuesday. (Xinhua/Hou Jie)