China saw continuous environmental improvement last year, with reductions in airborne pollutants in major polluted cities and severely polluted surface water across the country, authorities said.

Cities above prefecture level experienced fairly good air quality on 82 percent of the days in 2019, up by almost three percentage points year-on-year, according to the National Bureau of Statistics.

The bureau said such cities that have yet to see their PM2.5 particulate matter levels reach the national standard of 35 micrograms per cubic meter saw levels decrease by 2.4 percent.

China has a six-level air pollution system based on the air quality index. Air quality can be listed as fairly good with an index below 100.

The achievement was made thanks to the country's continuous efforts to upgrade major coal consumers, the Ministry of Ecology and Environment said.

By the end of last year, 86 percent of China's coal-fired power plants' installed capacity realized extra-low emissions. The emissions from over 780 million metric tons of crude steel production capacity in 23 provincial regions also reached extra-low levels.

Efforts were also made to help rural households shift from coal to clean energy to warm their homes during winter. Over 7 million rural households completed the shift in the Beijing-Tianjin-Hebei cluster in 2019, increasing the total number to 24 million.

The surface water across the country improved as well. While water with quality above Grade III, the third-highest of the country's five-tier surface water quality system, rose by 3.9 percentage points, water below Grade IV, the lowest quality, decreased by 3.3 percentage points.

The Yangtze River, the country's longest watercourse, witnessed even greater improvement in water quality, with that above Grade III up by 4.2 percentage points.

The ministry said it had managed to identify all wastewater drainage outlets in the Yangtze and its nine tributaries last year.

The top environmental watchdog registered 60,000 such outlets, over 30 times the number previously reported by local governments. It will roll out measures accordingly to intensify the governance of wastewater discharge.

Zhang Bo, the ministry's chief engineer, said, however, that environmental damage is still a common problem in many bodies of water across the country, and the ministry will beef up efforts to protect and restore the ecological system.

For example, bottom trawling for fish has been carried out in such an extreme manner in some regions that it has killed all aquatic plants in some water beds.

"The bottom of some lakes is a desert," Zhang said.

He said the ministry will set up buffer zones to prevent encroachment on water bodies.

"For all rivers and lakes in the country, big or small, there should be buffer zones," Zhang said. "Human activities should retreat from such zones as much as possible."