The proportion of various water quality in China’s coastal waters from 2015 to 2022 (%)
| Class I seawater area | Class II seawater area | Three types of seawater area | Four types of seawater area | Inferior to four types of seawater area | |
|---|---|---|---|---|---|
| 2015 | 33.6 | 36.9 | 7.6 | 3.7 | 18.3 |
| 2016 | 32.4 | 41 | 10.3 | 3.1 | 13.2 |
| 2017 | 34.5 | 33.3 | 10.1 | 6.5 | 15.6 |
| 2018 | 54.1 | 17.2 | 8.8 | 6.4 | 13.5 |
| 2019 | 46.6 | 30 | 7 | 4.7 | 11.7 |
| 2020 | 60.7 | 16.7 | 7.7 | 5.5 | 9.4 |
| 2021 | 66.8 | 14.5 | 5.2 | 3.9 | 9.6 |
| 2022 | 61.9 | 20 | 4.1 | 5.1 | 8.9 |
| Class I seawater area | Class II seawater area | Three types of seawater area | Four types of seawater area | Inferior to four types of seawater area | |
|---|---|---|---|---|---|
| 2015 | 33.6 | 36.9 | 7.6 | 3.7 | 18.3 |
| 2016 | 32.4 | 41 | 10.3 | 3.1 | 13.2 |
| 2017 | 34.5 | 33.3 | 10.1 | 6.5 | 15.6 |
| 2018 | 54.1 | 17.2 | 8.8 | 6.4 | 13.5 |
| 2019 | 46.6 | 30 | 7 | 4.7 | 11.7 |
| 2020 | 60.7 | 16.7 | 7.7 | 5.5 | 9.4 |
| 2021 | 66.8 | 14.5 | 5.2 | 3.9 | 9.6 |
| 2022 | 61.9 | 20 | 4.1 | 5.1 | 8.9 |
Source(s): According to the China Coastal Sea Environmental Quality Bulletin in 2020–2022