As of May 1, 2025, the Mediterranean Sea has officially become a Sulphur Oxides and Particulate Matter Emission Control Area (Med SOx ECA) under Annex VI of the MARPOL Convention. The sulphur content in fuel oil used by ships operating in the area is now limited to 0.1%, significantly reducing air pollution and delivering substantial benefits to both human health and the marine environment.

This new ECA enforces stricter sulphur content limits than the global standard (0.10% m/m compared to 0.50% m/m allowed outside SOx ECAs). Ships operating within these sulphur emission control areas, including the Mediterranean, are now subject to mandatory and rigorous measures to prevent, reduce, and control air pollution.

Reducing SOx emissions from maritime transport contributes to improved public health by lowering rates of lung cancer, cardiovascular diseases, stroke, and childhood asthma. The environmental benefits are equally significant, as decreased acidification helps protect crops, forests, and aquatic species. Additionally, this measure is expected to reduce ship-related haze, enhance visibility, and lower the risk of maritime accidents.

Maritime Routes in the Mediterranean

The Mediterranean Sea hosts some of the busiest maritime routes in the world, supporting approximately 20% of global seaborne trade. It is estimated that over 17% of the world’s cruise traffic and 24% of the global fleet navigate through the Mediterranean.

Med SOx ECA and Global Context

The Med SOx ECA is the fifth officially designated Emission Control Area under MARPOL Annex VI, alongside:

• The Baltic Sea area

• The North Sea area

• The North American ECA (covering designated coastal areas off the U.S. and Canada)

• The United States Caribbean Sea ECA (around Puerto Rico and the U.S. Virgin Islands)

In 2024, the IMO designated two additional ECAs: the Canadian Arctic and the Norwegian Sea. In April 2025, MEPC 83 approved a proposal to designate the North-East Atlantic as a future Emission Control Area.

On January 1, 2020, new global sulphur limits in fuel oil led to a 70% reduction in total sulphur oxide emissions from shipping, setting a maximum sulphur content of 0.5% outside emission control areas.