China has made historic breakthroughs in protecting water ecology and the environment in recent years, the Ministry of Ecology and Environment said Tuesday.

Through a battle against water pollution from 2018 to 2020, all cities at or above the prefecture level had eliminated 98.2 percent of the 2,914 "black and odorous" water bodies nationwide as of the end of last year, said ministry official Zhang Bo at a press conference.

All industrial parks in provincial-level regions or above had installed facilities for wastewater disposal, Zhang said. Cities at or above the county level had rectified more than 10,000 cases of irregularity concerning sources of urban potable water.

During the three-year period, the Yangtze River, China's longest river, saw water quality of its main stream rated at Grade II or above for the first time. Grade II is the second-highest within the country's five-tier water assessment system.

Looking ahead, Zhang said the ministry will extend the work on black and odorous water bodies to the county level with tailored solutions and set a blacklist for cities where such polluted water reemerges.

Efforts will also go into protecting water sources and speeding up ecological restoration in the country's major river basins, Zhang added.