MARPOL Annex VI (Prevention of Air Pollution from Ships) – Key Developments for 2026

Annex VI of the MARPOL treaty, introduced in 1997, is the IMO treaty which prevents air pollution from ships. It is an international regulatory framework which sets limits on certain emissions, whilst also addressing greenhouse gases and setting standards in Emission Control Areas.

Annex VI is periodically updated to tighten emissions standards, with several regulatory developments, including the key measures outlined below, taking effect  in 2026.

Enhanced IMO DCS Data Collection (MEPC.385(81)

Existing ships of 5,000 GT and above that did not voluntarily begin enhanced data collection in January 2025 are required to start gathering more granular fuel consumption and transport work data, effective from 1 January 2026.

This enhanced data collection forms part of the IMO Ship Fuel Oil Consumption Database (IMO DCS) and is intended to support the monitoring of operational carbon intensity.

The requirements include reporting fuel consumption by specific consumer groups (e.g., main engine, auxiliary engines, boilers) and making a distinction between when the ship is "underway" and when it is "not underway". 

All the data collected during the 2026 calendar year must be submitted for verification no later than 31 March 2027 in order for the ship to receive its Statement of Compliance (SoC).

Amendments to SEEMP (Ship Energy Efficiency Management Plan) apply (MEPC 395(82)

These amendments introduce clearer planning and reporting obligations aimed at helping ships reduce fuel use and fuel emissions.

SEEMP is now structured into 3 parts: 

• Part I - operational energy efficiency measures; 
• Part II - fuel oil data collection procedures; and 
• Part III - a carbon intensity improvement plan linked to the ship’s Carbon Intensity Indicator (CII) rating. 

Under the revised requirements, ships must report fuel consumption by engine type, record the use of shore power, provide distance travelled with cargo data, and identify any installed energy-saving technologies.

Flag administrations are responsible for verifying and approving SEEMP Parts II and III.

1 March 2026

Designation of the Canadian Arctic and the Norwegian Sea as Emission Control Areas (ECAs) for Nitrogen Oxides, Sulphur Oxides and Particulate Matter (as applicable) (MEPC.392(82); MEPC 82/17/Add.1, annex)

Emission Control Areas (ECAs) are designated maritime zones subject to strict rules which limit ship emissions and cover Sulphur Oxides (SOx), Nitrogen Oxides (NOx) and Particulate Matter (PM). Compliance requires the use of cleaner fuels or the installation of advanced abatement technologies in the areas designated as ECAs.

Existing ECAs include the Baltic Sea, the North Sea, the North American coastal areas, and the US Caribbean waters. These areas apply significantly lower fuel sulphur limits (0.10% vs. the global limit of 0.50%) and stricter NOx limits (Tier III).

Although the amendments formally designating the Canadian Arctic and the Norwegian Sea as new ECAs enter into force on 1 March 2026, the related compliance requirements will be phased in at later times.

For example, the stricter Tier III NOx limits for marine diesel engines above 130 kW will apply from 1 March 2026, but only for ships meeting specific construction criteria related to their building contract, the laying or construction of the keel or the delivery dates.

Meanwhile, the requirement for ships to use fuel with a sulphur content not exceeding 0.10% m/m (mass by mass) will become mandatory from 1 March 2027, i.e. 12 months after the amendments enter into force.

1 September 2026

Amendments to the NOx Technical Code 2008 (Certification of an engine subject to substantial modification or being certified to a Tier to which the engine was not certified at the time of its installation) (MEPC.398(83)

These amendments, due to take effect on 1 September 2026, bring further clarity to the certification procedure that follows (i) the substantial modification of an installed marine diesel engine or (ii) the allocation of a new Tier.

New flow charts for a better understanding of the survey and certification process of marine diesel engines are also introduced.

16-27 November 2026

Extraordinary session of the IMO’s Marine Environment Protection Committee (MEPC) (adoption of the IMO Net Zero Framework and designation of North-East Atlantic as an ECA)

As readers will recall, the second extraordinary session of the IMO’s Marine Environment Protection Committee (MEPC/ES.2), held over 14-17 October 2025, failed to adopt the resolution amending MARPOL Annex VI, and, in particular, the measures leading to the creation of the IMO Net-Zero Framework.

The Committee agreed to adjourn the session for 12 months and, in the interim, to continue its work on the amendments and on building consensus among Member States.

The adjourned session is scheduled to reconvene on 16-27 November 2026, with the aim of adopting both the revised Net Zero Framework and the designation of the North-East Atlantic as an ECA for SOx, PM and NOx.

Net Zero Framework

The IMO Net-Zero Framework is a set of new international regulations aimed at reducing greenhouse gas (GHG) emissions from ships, in line with the IMO's 2023 GHG Strategy.

The IMO Net-Zero Framework was approved at the MEPC 83 session, in April 2025, as a new Chapter 5 of the Draft Revised Annex VI of MARPOL. It includes two key elements: a global fuel standard and a global GHG emissions pricing mechanism.

The global fuel standard would require ships to gradually reduce the pollution levels of the fuels they use (measured by the GHG emissions produced per unit of energy used, across a fuel's life cycle). 

In parallel, a mandatory emissions intensity limit would apply. The associated pricing mechanism would impose a charge on the GHG emitted by ships to encourage the industry to lower emissions and achieve compliance with the global fuel standard.

The main areas of contention during the 2025 extraordinary session included: 

• concerns over the pace of transition compared with the realistic availability of alternative fuels;
• the potential economic impact on developing states and smaller operators; 
• the risk of retaliatory levies by certain states; 
• questions around the scalability and readiness of alternative fuels; and 
• uncertainty over how the proposed economic mechanism would function in practice.

If it were to be adopted, the IMO Net Zero Framework would operate alongside the FuelEU Maritime Regulation, resulting in overlapping regulatory regimes that would force ship operators to reduce GHG intensity.

However, if the IMO-proposed system is assessed as sufficiently effective, the European Commission is expected to review the FuelEU Maritime Regulation to avoid duplication and conflicting requirements. Until that time (assuming the IMO Net Zero Framework is adopted), shipowners may have to operate two separate, though similar, datasets for the same ships and they could find themselves exposed to two distinct, potentially high, penalty regimes in case of non-compliance.

Designation of North-East Atlantic Ocean as a new ECA

The formal designation of the North-East Atlantic Ocean as a new ECA (as discussed above) would, if adopted in the same terms proposed in October 2025, create the world’s largest ECA and result in the significant reduction of ship emissions of SOx, NOx and PM across the territorial seas and Exclusive Economic Zones of Greenland, Iceland, the Faroe Islands, Ireland, the United Kingdom, France, Spain and Portugal. Ships operating in this extensive area would be required to adhere to a 0.10% sulphur fuel limit.

Additionally, ships constructed on or after 1 January 2027, meaning the building contract is placed on or after that date, or alternatively, ships for which the keel is laid (or is at a similar stage of construction) on or after 1 July 2027, or where the delivery is on or after 31 January 2031, would have to meet Tier III NOx emissions standards.