The State Oceanic Administration (SOA) on Wednesday disclosed the findings of a nationwide survey on land-based sources of marine pollution.
A total of some 9,600 such sources, including about 740 rivers, 7,500 sewage outlets and 1,350 emergency flood outlets, were identified in the survey.
Among the sewage outlets, only 8 percent were licensed, and about one-quarter were established in ecologically sensitive areas such as protection zones, off-shore wetlands and fisheries, according to the SOA.
The SOA found, on the basis of the data in the past five years, the marine environment near more than 80 percent of sewage outlets failed to meet standards.
In addition, about 80 percent of the marine ecosystem under watch was rated unhealthy or sub-healthy.
To address the issue, the SOA will strictly supervise sources of pollution to seawater and introduce real-time monitoring.
More will be done to close the illegal sewage outlets and control the number of those used by aquaculture.