Emission control areas (ECAs) are sea areas in which stricter controls were established to minimize airborne emissions from ships as defined by Annex VI of the 1997 MARPOL Protocol.
The emissions specifically include SOx, NOx, ODSs (Ozone Depleting Substances) and VOCs and the regulations came into effect in May 2005. Annex VI contains provisions for two sets of emission and fuel quality requirements regarding SOx and PM (Particulate Matter), or NOx, a global requirement and more stringent controls in special emission control areas (ECA). The regulations comes from concerns about “local and global air pollution and environmental problems” from the shipping industry. In January 2020, a revised more stringent Annex VI was enforced in the emission control areas with significantly lowered emission limits as stated below :
| before 1 January 2012 | 4.50% m/m |
| between 1 January 2012 and 1 January 2020 | 3.50% m/m |
| after 1 January 2020 | 0.50% m/m |
ECA areas ( as on 2023) as designated by the IMO :
- The North American area
- The Unites States Caribbean sea area
- The Baltic Sea area
- The North Sea area
