This combination photo shows the Langjiang River in Liuzhou city, South China's Guangxi Zhuang autonomous region, in 2018 (top) and the Langjiang River covered with water hyacinth, a rapidly growing floating plant in 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)