The Tangshan and Qinhuangdao harbours, both in the Bohai Sea area, are ranked fourth and ninth nationwide in terms of container flow capacity, with more than 253,000 vessels plying into the sea, the Economic Information Daily reported.
Analysts have attributed the ecological deterioration to the lack of local government regulations as well as the lack of coordination and cooperation between different regions surrounding the sea.
Zhang Meizhi, a member of the Chinese People's Political Consultative Conference from Hebei Province, said many cities surrounding the Bohai Sea have failed to assign people to tackle maritime pollution.
She said maritime pollution monitoring teams have limited resources or lack manpower.
Analysts have also called for the enactment of a specific law to tackle pollution in the Bohai Sea.
"Local authorities need to strengthen supervision and increase penalties on enterprises' pollution discharge," Ma said.