China's efforts in beefing up sewage management has brought significant improvement to water quality in the country's longest watercourses and largest enclosed sea, according to the Ministry of Ecology and Environment.

The ministry has managed to figure out the locations of all sewage outlets that empty into the Yangtze River and the Bohai Sea, after it rolled out campaigns to screen for such outlets in 2019, said Vice-Minister Qiu Qiwen at a news conference organized by the State Council Information Office on Saturday.

In the Yangtze River, Asia's longest, 60,292 outlets have been located, which is 30 times of the previously registered number, he said. The number of outlets that empty into Bohai Sea has been updated to 18,886, compared with the previous less than 800.

Qiu also noted significant progress in tracing the sources of sewage and rectifying problems in these outlets.

As of the end of 2021, the sources of 80 percent of the outlets in the Yangtze and Bohai had been identified, he said. Over 8,000 violations in sewage discharge have been addressed.

The endeavor has resulted in "historical breakthrough" in water quality in the Yangtze, he said. Unprecedentedly, the river saw water quality of Grade II, the second-best level in the country's five-tier quality system for surface water, in all sections of its trunk in the end of 2020 and all through last year.

Compared with the 2018 level, the proportion of water with fairly good quality in Bohai's coastal area in 2021 increased by 16.9 percentage points, he noted.

China has a four-tier quality system for sea water. The quality of sea water is considered as being fairly good if it is at Grade II or above.