22 April 2025

by Adam James

IMO’s MEPC 83 Approves Key Steps Toward Maritime Decarbonisation and Pollution Control

The 83rd session of the International Maritime Organisation’s Marine Environment Protection Committee (MEPC) concluded on April 11, 2025, marking a pivotal moment in the global effort to decarbonise shipping and reduce marine pollution.

The session finalised draft amendments to MARPOL Annex VI, setting the stage for the IMO’s net-zero greenhouse gas (GHG) strategy. If adopted at the extraordinary MEPC session in October 2025, these rules will come into force on March 1, 2027.

Key regulations include fuel use and emissions data collection from 2028, mandatory annual reporting from 2029, and a progressive GHG Fuel Intensity (GFI) reduction trajectory through 2040. Yachts over 5,000 gross tonnage will be subject to the same rules as commercial vessels. The measures also support alternative fuels, including hydrotreated vegetable oils (HVO), with financial incentives for ultra-low-emission technologies.

MEPC 83 also adopted major amendments to the NOx Technical Code, allowing marine diesel engines to operate with multiple emissions profiles and updated testing standards. These changes, effective from 2027, aim to give shipowners more flexibility while tightening emissions control.

In a further move to protect marine ecosystems, the Committee approved the creation of a new Emission Control Area (ECA) in the North-East Atlantic Ocean, encompassing parts of the UK, Ireland, Iceland, and the Iberian Peninsula. This ECA will enforce stricter NOx and SOx limits beginning in 2027 and 2028, respectively.

The Committee also gave the green light for two new Particularly Sensitive Sea Areas (PSSAs) off the coast of Peru, where strict environmental protections will apply.

With an expanded work programme through 2027, including new regulations on biofouling, non-carbon fuels, and ammonia emissions, MEPC 83 solidified the IMO’s commitment to greener, safer oceans.

British Members have access to this and previous reports:

IMO Meeting Reports: British Marine

Members can also obtain guidance and advice by emailing technical@britishmarine.co.uk