CII
Carbon Intensity Indicator
Meaning
CII (Carbon Intensity Indicator) is the IMO's yearly A-to-E rating of a ship's operational CO2 emissions per unit of transport work.
Also written as CII rating
CII explained
Ships of 5,000 GT and above get a CII rating every year based on fuel burned and distance sailed. A ship rated D for three years in a row, or E in one year, must submit a corrective action plan.
Waiting time, slow cargo operations and long ballast legs worsen the rating, so owners increasingly ask charterers to cooperate on speed and routing.
Related terms
EEXI
EEXI is the IMO's one-off technical efficiency standard for existing ships, in force since 2023, often met by limiting engine power.
EU ETS
The EU ETS requires shipping companies to buy and surrender carbon allowances (EUAs) for CO2 emitted on voyages to, from and within the EU.
FuelEU Maritime
FuelEU Maritime is an EU rule, in force since 2025, that caps the greenhouse gas intensity of energy ships use on EU voyages and tightens over time.