Technicians from State Grid Suqian Power Supply Co operate a drone while checking transmission towers along a river in Suqian, Jiangsu province. As the East China region enters plum rain season, the local power grid operator is ramping up maintenance work for the Suqian section of the±800 kilovolt direct current transmission corridor that stretches from Xiliin Gol League in the Inner Mongolia autonomous region to Taizhou in Jiangsu.