BEIJING, Feb. 27 -- China made steady progress in improving its ecological water systems last year, with continued declines in pollutant discharge and improved water quality in rivers and lakes.

Two main parameters for water pollutants -- chemical oxygen demand and ammonium nitrogen -- dropped 3.7 percent and 5.5 percent year on year in 2022, respectively, data from the Ministry of Ecology and Environment (MEE) showed.

The good-quality surface water, at or above Grade III in China's five-tier system, accounted for 87.9 percent of the total, up from 84.9 percent in the previous year. The Yangtze River, the country's longest waterway, saw all its mainstreams report even better Grade II quality for a third straight year, and the Yellow River, the second longest, reached the level for the first time.

"New notable progress has been made in protecting the ecological water environment," Huang Xiaozeng, an MEE official, said.

The achievements came as a result of China's strengthened efforts to keep waters clear last year.

A three-year program was initiated to toughen the supervision of sewage outfalls into rivers, lakes, and the sea. So far, environmental inspectors have screened some 245,000 kilometers of shorelines to identify nearly 230,000 sewage outlets, with about one-third rectified.

An action plan advanced the protection and restoration of the Yangtze River basin. Over 90 percent of outfalls along the Yangtze have been successfully traced, and targeted efforts were made to tackle the pollution from industrial parks in the basin.

The protection of drinking water sources was intensified, with 19,600 township-level protection zones designated across the country and problems in over 2,800 water sources rectified.

Ecological governance also improved. With new guidelines on the sewage discharge permit system, some 3.44 million fixed pollution sources nationwide were brought under government management.

While water protection has gained remarkable results, there are still bottlenecks and urgent challenges.

Huang cited stubborn black and odorous water bodies in cities, inadequate pollution control in some regions, and ecological water imbalances, including Cyanobacteria blooms.

The focus will now be improving the quality of the water environment, with targeted pollution control, strengthened protection in key river basins, and enhanced governance systems, Huang said.

The official, in particular, stressed unwavering efforts to purify urban water bodies, address problematic sewage outfalls, rein in lake pollution, and push forward in protecting and restoring the Yangtze River basin.