CII after 2026: the line tightens every year

In brief

Instrument

MARPOL Annex VI, regulation 28; guidelines MEPC.352(78) to MEPC.355(78); reduction factors MEPC.400(83)

Ships in scope

5,000 GT and above, of the types the regulation lists

Rating

A to E, for each calendar year

Reduction against 2019

11 % (2026) · 13.625 % (2027) · 16.25 % (2028) · 18.875 % (2029) · 21.5 % (2030)

Corrective action

Three consecutive years at D, or one year at E, requires a corrective action plan

SEEMP Part III

Revised by 31 Dec 2025, with an implementation plan for 2026 to 2028

How a rating is made

The attained CII divides the CO₂ a ship emitted in a year by the work it could have done: its capacity multiplied by the distance it sailed. That figure is set against a required value for the ship’s type and size, which is the 2019 reference line reduced by the year’s factor. Where the ship lands between the rating boundaries gives the letter.

Why the whole year counts

A rating is decided by twelve months, not by one voyage. A slow first quarter, a hull fouling between dockings or a change of trade all reach the letter months later, when there is least time left to recover it.

From D to a plan

A ship rated D for three consecutive years, or E in any one year, must carry a corrective action plan in Part III of its Ship Energy Efficiency Management Plan, setting out how the required value will be met. The revised Part III that took effect for 2026 already looks three years ahead.

What to check

• Each ship’s required CII for 2027, from its type, size and the 13.625 % factor.
• Ships trending towards D this year, while there are still months to change it.
• Whether each SEEMP Part III still matches the trade the ship is in.

Our reading at 8 Oct 2026, for planning. Not legal advice; the authority’s current text decides.

Sources

• MARPOL Annex VI, regulation 28
• Resolutions MEPC.352(78) to MEPC.355(78)
• Resolution MEPC.400(83)