The Mediterranean Sea officially became an Emission Control Area for Sulphur Oxides and Particulate Matter (Med SOx ECA) under MARPOL Annex VI on May 1, 2025. 

Ships operating in the area must now use fuel oil with a maximum sulphur content of 0.1%, a significant reduction that aims to curb air pollution and provide major health and environmental benefits.

Vessels in ECAs, including the Mediterranean, are subject to strict air pollution regulations. The Med SOx ECA enforces a sulphur limit of 0.10% mass by mass (m/m), compared with the global cap of 0.50% m/m outside these zones.

Reducing SOx emissions from maritime traffic lowers the risk of lung cancer, cardiovascular disease, strokes, and childhood asthma. 

The environment also benefits from reduced acidification, which helps protect crops, forests, and marine ecosystems. Additionally, cutting emissions improves visibility by limiting haze, thereby reducing the risk of maritime accidents.

The Mediterranean Sea supports 20% of global seaborne trade and is one of the world's busiest maritime corridors. An estimated 17% of all cruises and 24% of the global fleet operate in the region.

The Med SOx ECA is the fifth Emission Control Area designated under MARPOL Annex VI, joining the Baltic Sea, North Sea, North American coastal areas, and the United States Caribbean Sea ECA. In 2024, the IMO added the Canadian Arctic and the Norwegian Sea to the list.

In April 2025, MEPC 83 approved the designation of the North-East Atlantic as an ECA.

Since January 1, 2020, global sulphur limits have contributed to a 70% reduction in total SOx emissions from shipping, with fuel regulations capping sulphur content at 0.5% outside ECAs.