Children of Yangxi Primary School learn how to test water quality of a river in Changle Village, Zhili Town of Huzhou City, east China's Zhejiang Province, March 22, 2017. Wednesday marks the World Water Day. (Xinhua/Xu Yu)
Children of Yangxi Primary School learn how to test water quality of a river in Changle Village, Zhili Town of Huzhou City, east China's Zhejiang Province, March 22, 2017. Wednesday marks the World Water Day. (Xinhua/Xu Yu)