This combination photo shows a law enforcement vessel patrolling the Langjiang River in Liuzhou City, south China's Guangxi Zhuang Autonomous Region, Nov. 5, 2018 (top) and cleaners clearing the water hyacinth, a rapidly growing floating plant, on the Langjiang River, May 8, 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)