This combination photo shows the Langjiang River in Liuzhou City, south China's Guangxi Zhuang Autonomous Region, Dec. 16, 2018 (top) and the Langjiang River covered with water hyacinth, a rapidly growing floating plant, May 3, 2017 (bottom). Measures had been taken in recent over a year to clear the water hyacinth to protect the water environment in the 10-kilometer-long Langjiang River. (Xinhua/Li Hanchi)