As a result of the continuous efforts of the Seoul Metropolitan Government (SMG), the water quality of the Hangang River, which flows across Seoul, has become cleaner. In 2020, every index that evaluates the water quality of the Hangang River has exceeded the target value that was set by the Ministry of Environment (MOE).

This is due to various policies executed by the SMG, including the water pollution cap. The water pollution cap is a system in which the quantity of pollutants that flow into the river is controlled not to exceed the set total quantity. Each autonomous district must control the water quality to attain and maintain the target quality set by the MOE, and if not, development activities are limited.

The SMG has implemented diverse policies aside from the water pollution cap for effective improvement of water quality. It has strengthened the criterion of the quality of the water that is discharged from four sewage treatment centers so that it becomes tighter than legal criteria, monitored the water quality through 82 water quality measure networks and responded to any risks.

In the second half of this year, the SMG will be setting the action plan for the second-step water pollution cap (2021–2030). The SMG will achieve the water quality goal for 2030 set by the MOE, and find various ways for a clean and safe water environment.