What is CII? Carbon Intensity Indicator explained

The Carbon Intensity Indicator, CII, is the number the International Maritime Organization uses to grade how cleanly a ship is operated across a calendar year. It’s an output metric, not a design metric. A vessel earns its CII from what it actually did: the fuel it burned, the distance it sailed, and the tonnage it could have carried. The grade lands somewhere on a five-letter scale from A to E, and that letter follows the ship into its certificates, its charter negotiations, and its lender’s screening file. If you want to model the number for a specific ship before the year closes, the CII Attained calculator takes ship type, capacity, distance, and each fuel burned and returns the attained value, the required value, and the rating in one view.

The legal spine is short and worth memorizing. MEPC.336(76) was adopted at the 76th session of the Marine Environment Protection Committee in June 2021. It entered force on 1 November 2022 as Regulation 28 of MARPOL Annex VI, and the first measured reporting year was the 2023 calendar year, with the first ratings issued in 2024. Four guidelines resolutions adopted at the same session do the arithmetic that the regulation only points to: MEPC.337(76) sets the reference lines, MEPC.338(76) sets the year-on-year reduction factors, MEPC.339(76) defines the rating boundaries, and a 2022 pair, MEPC.354(78) and MEPC.355(78), refined the reduction factors & added correction factors and voyage adjustments. The regulation is the trigger; the guidelines are the formulas.

How CII came to exist

CII didn’t arrive out of nowhere. It’s the operational half of a package the IMO had been building since the Initial GHG Strategy of 2018, which set a target to cut total annual shipping emissions by at least 50% by 2050 against a 2008 baseline and to reduce carbon intensity per transport-work by at least 40% by 2030. The design-side tool, EEDI, had already been mandatory for newbuilds since 2013, but EEDI says nothing about a ship once it’s trading. The committee needed a metric that gripped the existing fleet and graded actual operation, and the work that became CII ran through several MEPC sessions before it was adopted.

The data foundation came first. The IMO Data Collection System, mandatory from 2019, already required ships of 5,000 GT and above to report annual fuel-oil consumption, distance, and hours under way to their flag administration, which forwards the aggregate to the IMO. That dataset gave the committee both the 2019 reference-line baseline and a ready-made reporting pipe, which is why CII scope and DCS scope are identical. Building CII on top of DCS meant no new onboard measurement equipment and no new reporting cycle, just a rating layer applied to numbers ships were already filing.

The adoption itself happened at MEPC 76 in June 2021, where EEXI and CII were adopted together as a single amendment package to Annex VI. The package entered force on 1 November 2022 under the tacit-acceptance procedure, and the 2023 calendar year became the first one measured. A year later, at MEPC 78 in June 2022, the committee refined the reduction factors through MEPC.354(78) & added the correction factors and voyage adjustments through MEPC.355(78), tidying up the parts of the first version that operators had flagged as unworkable on certain trades.

What CII measures, and what it deliberately ignores

CII is a ratio of emissions to transport-work potential. The numerator is the ship’s annual carbon dioxide output in grams, derived from fuel burned and a per-fuel carbon factor. The denominator is capacity times distance: how much the ship could carry, multiplied by how far it went. The result is grams of CO2 per capacity-mile, and lower is better.

That denominator is the controversial part. For most cargo ships the regulation uses deadweight tonnage, not cargo actually carried. A bulk carrier that sailed 40,000 nautical miles half-empty is credited with the same capacity-miles as one that ran full, because the formula doesn’t see the cargo, only the deadweight & the distance. This is the Annual Efficiency Ratio, AER, and it’s a proxy. It was chosen because deadweight and distance are already collected under the IMO Data Collection System, so no new measurement burden falls on the ship. The cost of that convenience is that CII rewards moving a hull through the water efficiently, not moving cargo efficiently.

What the metric ignores is just as telling. It doesn’t see methane slip from low-pressure dual-fuel engines, so an LNG-burning ship can post a strong CII while leaking unburned methane that never enters the carbon-factor arithmetic. It doesn’t see upstream or well-to-tank emissions; those are picked up by FuelEU Maritime, not CII. And it doesn’t distinguish a laden voyage from a ballast leg. The ship that runs empty to reposition for the next fixture is penalized the same as one that wasted fuel, because both burned bunkers and neither one’s cargo enters the sum.

The attained CII: the AER formula

The attained CII is the number the ship earned. For bulk carriers, tankers, gas carriers, container ships, general cargo ships, refrigerated cargo carriers, and combination carriers, the IMO uses the AER, where the denominator is deadweight times distance.

Read the card carefully because two inputs trip people up. The carbon factor, written as Cf, converts a tonne of a given fuel into tonnes of CO2. It isn’t one number. VLSFO and HFO sit at 3.114, marine gas oil at 3.206, LPG propane near 3.000, and LNG at 2.750. Burn a mix and you sum each fuel’s contribution separately before dividing. The second trap is the capacity term. Deadweight is the default, but the regulation switches to gross tonnage for ro-pax ships, ro-ro vehicle carriers, and cruise ships, because deadweight understates the transport work those passenger and vehicle vessels actually perform. The cgDIST variant, CO2 over gross-tonnage-times-distance, is the same shape with GT swapped in for DWT.

A worked feel for the scale helps. Take a Supramax bulk carrier of 56,000 dwt that sailed 55,000 nautical miles in 2023 and burned 6,200 tonnes of VLSFO. The CO2 is 6,200 times 3.114, which is 19,307 tonnes, or 19.307 billion grams. Divide by 56,000 dwt times 55,000 miles, which is 3.08 billion dwt-miles, and the attained AER is roughly 6.27 grams of CO2 per dwt-mile. Whether that’s an A or an E depends entirely on what the required line says for a 56,000-dwt bulker in 2023, which is the next piece.

The carbon factors that drive the numerator

The Cf term is where a lot of CII arithmetic goes wrong, so it’s worth setting out properly. Cf is the conversion factor from one tonne of a fuel to the tonnes of CO2 that fuel releases when burned, and the IMO fixes the values rather than letting operators measure them. A tonne of heavy fuel oil or very-low-sulphur fuel oil produces 3.114 tonnes of CO2. Marine gas oil and marine diesel oil sit higher at 3.206, because the lighter distillate has a higher carbon content per tonne. Liquefied natural gas comes in at 2.750, the lowest of the common fuels on a tank-to-wake basis, which is the headline reason LNG looks good under CII. LPG runs around 3.000 for propane and 3.030 for butane, and methanol, far lower in carbon per tonne, sits near 1.375.

Those numbers are tank-to-wake only. CII counts the carbon that leaves the funnel and nothing else. It doesn’t count the energy or emissions to extract, refine, and ship the fuel to the bunker barge, and it doesn’t count unburned methane that slips through a low-pressure dual-fuel engine at part load. That second omission is the one that flatters LNG: a ship can post a strong CII on the 2.750 factor while its real climate footprint, methane being a far stronger greenhouse gas than CO2 over a 20-year window, is worse than the grade suggests. The well-to-wake accounting that captures both upstream emissions and methane slip lives in FuelEU Maritime, not CII, which is one reason the two regimes can reward opposite behavior on the same ship.

When a ship burns several fuels in a year, and most do, you compute each fuel’s CO2 separately and sum them before dividing by capacity-distance. A ship that burned 5,000 tonnes of VLSFO and 800 tonnes of MGO produces 5,000 times 3.114 plus 800 times 3.206, which is 15,570 plus 2,565, for 18,135 tonnes of CO2. Mixing the factors into a single average is a common error and it skews the result toward whichever fuel dominated, so the per-fuel sum is the only correct route. The SFOC-to-CII quick check handles the fuel-mix arithmetic when you’re working from specific fuel-oil consumption rather than annual totals.

The required CII: reference line minus a yearly cut

The required CII is the target the ship has to beat. It’s built in two moves. First, a reference line gives the 2019 fleet-average intensity for a ship of that type and size. Then an annual reduction factor pulls the target down a little more each year, so the bar keeps rising even if a ship never changes how it operates.

The reference line is a power curve: a coefficient times capacity raised to a negative exponent. The coefficient and exponent come from MEPC.337(76), one pair per ship type, calibrated against 2019 IMO DCS data. Larger ships sit lower on the curve because they’re more efficient per tonne-mile, which is why a 300,000-dwt VLCC and a 56,000-dwt Supramax don’t share a target even though both are tankers or bulkers by family.

The reduction factor, written Z, is the part that bites year after year. MEPC.338(76) set it at 5% for 2023, then it tightens to 7% in 2024, 9% in 2025, and 11% in 2026, each measured against the 2019 reference line. That’s a flat 2 percentage points a year through 2026. Beyond 2026 the figure isn’t settled; the IMO has been reviewing the trajectory toward its GHG strategy targets, and the post-2026 reduction schedule is part of that review rather than a fixed number you can quote today. To compare what a ship earned against what it owed, the CII attained-vs-required check shows the headroom or the deficit directly.

Going back to the Supramax: if MEPC.337(76) put the 2019 reference line for a 56,000-dwt bulker at, say, 7.0 grams per dwt-mile, the 2023 required CII after the 5% cut is 7.0 times 0.95, which is 6.65. The ship’s attained value of 6.27 is below that, so it’s compliant, and the margin decides the letter grade. By 2026, with an 11% cut, the same reference line yields a required CII of 6.23, and that 6.27 attained value would now fail unless the operator found roughly half a gram of intensity somewhere. That’s the tightening at work: the ship didn’t get worse, the target moved under it.

The A-to-E rating bands

The rating compares attained against required and sorts the ratio into five bands. The boundaries are four numbers, d1 through d4, that MEPC.339(76) tabulates separately for each ship type. They’re sometimes called the dd vectors. A ratio below d1 is an A, between d1 and d2 a B, between d2 and d3 a C, between d3 and d4 a D, and above d4 an E.

The letters carry weight beyond a score. C is the pass line: a ship rated C met its required CII for the year and needs no remedial action. A and B are superior, and some ports and charterers attach incentives to them, though those incentives are commercial choices, not regulation. D and E are where the regulation reaches into the next year’s operations.

The trigger mechanism is precise. A ship rated D for three consecutive years, or rated E in any single year, must develop a corrective action plan as part of its SEEMP Part III. That plan is added to the Ship Energy Efficiency Management Plan, submitted to the flag administration or a recognized organization, and verified before the next Statement of Compliance is issued. The ship isn’t detained and isn’t fined under MARPOL for a poor CII; the consequence is a documented plan and the verification gate on its certificate. The commercial consequences, covered below, tend to bite harder than the regulatory ones.

SEEMP Part III and the corrective-action plan

The SEEMP has three parts, and CII reshaped the third. Part I is the energy-efficiency management plan that’s existed since 2013. Part II is the data-collection plan that feeds the IMO DCS. Part III, the enhanced plan, became mandatory for in-scope ships from 1 January 2023. It has to state the required CII for the next three years, set out the operational measures the ship will use to meet them, and describe how the operator will check progress against the plan.

When a ship trips the D-three-years or single-E threshold, the corrective action plan is folded into that Part III. It can’t be vague. It needs to lay out the specific measures: a speed-management policy, a hull-cleaning interval, a weather-routing change, a retrofit timetable, whatever the operator commits to, plus a self-evaluation showing how each measure should move the number. The corrective-trajectory calculation is the planning tool here, projecting the year-on-year path a ship has to walk to climb back to a C.

The verification is the teeth. Without an approved corrective plan, the flag state or recognized organization won’t endorse the Statement of Compliance, and a ship without a current SoC has a trading problem the moment a port-state control officer asks for it. So the practical force of a poor CII isn’t a fine, it’s an administrative chokepoint at the next survey window.

From DCS data to a rating: the annual cycle

The rating runs on a fixed calendar. A ship reports its fuel-oil consumption, distance traveled, and hours under way for the calendar year through the DCS, normally by 31 March of the following year, to its flag administration or recognized organization. The administration verifies the data and issues a Statement of Compliance for the DCS within five months of the year-end, by 31 May. That same verified dataset is what the attained CII is computed from, so there’s no separate CII measurement step; the rating is a calculation applied to data already filed and confirmed.

The attained CII is then compared against the required CII for that ship type, size, and year, and the ratio drops into one of the five bands. The rating is documented and, where it’s a D for a third straight year or an E for a single year, the corrective-action obligation kicks in for the following period. Because the cycle is annual and backward-looking, an operator never sees the final grade until the year is closed and the data verified, which is exactly why mid-year modeling against the CII attained calculator matters: by the time the official rating lands, the operating decisions that set it are months in the past.

One quirk of the calendar trips up new entrants. A ship delivered or first entering the regime partway through a year reports only its in-scope period, and the rating logic is applied on that basis, but the year-on-year reduction factor still keys to the calendar year, not to the ship’s months in service. A vessel that starts trading in mid-2025 is graded against the 2025 required line built on a 9% reduction, the same as a ship that ran the full twelve months, so a short first year offers no relief from the tightening schedule.

Which ships are in scope, and which aren’t

CII scope tracks the IMO Data Collection System, which is the cleanest way to remember it. If a ship reports fuel-oil consumption data under the DCS, it’s in the CII regime. That means cargo ships of 5,000 gross tonnage and above on international voyages, plus ro-pax and cruise ships above the same threshold. The 5,000 GT line is the same one that defines DCS reporting, which is why the two regimes overlap so neatly.

The exclusions matter for anyone running a mixed fleet. Ships below 5,000 GT are out. Ships on domestic voyages that aren’t subject to MARPOL Annex VI as international traders are out. Fishing vessels, offshore drilling rigs and other non-self-propelled or special-purpose offshore units, warships and naval auxiliaries, and ships not propelled by mechanical means all sit outside. A platform supply vessel or an anchor-handling tug, the workhorses of the offshore sector, generally falls outside CII even above 5,000 GT, because of the offshore exclusion and the nature of its service. The boundary cases, dredgers, cable-layers, and the like, turn on flag-state interpretation of the ship-type definitions, and operators of those vessels should confirm classification with their administration rather than assume.

Ship type isn’t just an in-or-out switch. It selects the entire arithmetic: which capacity term applies, deadweight or gross tonnage, which reference-line coefficients from MEPC.337(76) the ship uses, and which set of d1-to-d4 boundaries from MEPC.339(76) sort it into a grade. A bulk carrier and a cruise ship of identical gross tonnage are graded on different curves entirely, because they do different work.

Correction factors and voyage adjustments

The raw AER overstates the intensity of ships doing certain kinds of work, so MEPC.355(78) introduced correction factors and voyage adjustments, the G5 guidelines, to take some of those distortions out before the rating is struck. The idea is simple: subtract the fuel or the distance attributable to a non-transport activity so the ship isn’t graded on emissions it had no efficient way to avoid.

The recognized adjustments cover a defined list. Ships with ice class get a correction for the extra power they burn in ice or because of strengthened, heavier hulls. Time spent in ship-to-ship transfer operations, the kind covered under Annex I Reg.41 for oil cargo, can be deducted because the fuel burned holding station isn’t moving cargo anywhere. Electrical power drawn by reefer containers, cargo cooling that’s a service rather than propulsion, qualifies for a correction on container and reefer ships. Shuttle tankers with dynamic positioning, certain gas carriers using cargo as fuel, and a handful of other defined cases each have their own treatment in the guidelines.

The adjustments are not a free pass. Each one has eligibility conditions, has to be documented in the SEEMP and the verification file, and only covers the specific listed activity. A ship can’t deduct fuel for a slow port approach or for waiting at anchor under these rules; idle time at anchor still counts against the ship even though it produced zero transport work, which is one of the standing criticisms below. The voyage-adjustment math is fiddly enough that getting it onto a calculator, as in the CII voyage-adjustment tool, is the difference between a defensible filing and a guess.

How CII relates to EEXI, EU ETS, and FuelEU

CII doesn’t operate alone. It sits in a stack of overlapping rules, and the interactions decide where an operator spends money. The first pairing is internal to the IMO: EEXI and CII landed together under the 2021 amendments. EEXI is a one-time design check that every existing ship above 400 GT had to pass by its first annual, intermediate, or renewal survey on or after 1 January 2023, usually met with an engine power limitation or shaft power limitation as set out in the EPL and ShaPoLi guidance. EEXI caps the installed power; CII grades the operation. A ship can be EEXI-compliant and still post an E if it’s run hard, because EEXI limits the ceiling while CII measures the actual flight.

The relationship to EEDI is the same shape one design generation back. EEDI is the newbuild design metric; CII is the operational one. The two answer different questions, design efficiency versus operational efficiency, and a hull that aced its EEDI at delivery can drift into a poor CII a decade later through fouling, slow maintenance, or a trade pattern full of ballast legs.

The regional rules are where the double-counting starts to hurt. EU ETS for shipping phased in carbon allowances on emissions from voyages touching EU ports from 2024, and FuelEU Maritime put a declining greenhouse-gas-intensity limit on the energy used onboard from 2025. Neither replaces CII; they stack on top of it for any ship trading in European waters. A 2024 voyage from Rotterdam to Singapore can be counted under three regimes at once: CII for the IMO grade, EU ETS for the allowance surrender, and FuelEU for the energy-intensity check. The metrics measure different things, so improving one can pull against another. CII rewards low CO2 per dwt-mile; FuelEU rewards low well-to-wake GHG intensity including methane slip, which CII ignores. The reporting plumbing for the IMO side versus the EU side is itself a known headache, set out in the IMO DCS vs EU MRV comparison.

What an operator can actually do to move the grade

CII is operational, so operational levers dominate. The single largest is speed. Main-engine fuel consumption scales roughly with the cube of speed, so a 10% speed cut drops main-engine fuel by close to 27%, though auxiliary load is flatter and erodes some of that. Slow steaming is the most powerful CII lever there is, and the operational side of it is laid out in the dedicated slow steaming and CII article. The catch is that sustained slow steaming changes how the engine ages and fouls, which is why the engine-cleanliness and derating angles get their own treatment.

Hull and propeller condition come next. Marine fouling can add 15% to 30% to hull resistance over a docking cycle, and the fuel to push through that resistance lands straight in the CII numerator. Scheduled in-water hull cleaning and propeller polishing claw it back. Weather routing to dodge adverse currents and head seas, trim optimization for the actual loading condition, and just-in-time arrival to cut waiting time off the port all add single-digit-percent gains that compound across a year.

Then there are the capital measures. Energy-saving devices, pre-swirl stators, ducts, air lubrication, and wind-assist rotor sails or suction wings cut the power needed at a given speed. Fuel switching changes the carbon factor directly: moving from VLSFO at 3.114 to LNG at 2.750 cuts the per-tonne CO2 by roughly 12% before accounting for the methane slip that CII doesn’t measure. Each of these has a payback that depends on the ship’s trade, its fuel price exposure, and how close it sits to a rating boundary. A ship one decimal place inside a C has different economics from one that’s already an E.

The boundary effect deserves its own note because it changes how operators spend. The grade is a step function, not a sliding scale, so the marginal value of a 1% intensity cut depends entirely on where the ship sits relative to the d1-to-d4 lines. A ship deep inside its C band gains nothing visible from a small improvement; the same improvement on a ship sitting just over the d3 line into D can flip the letter and lift the corrective-plan obligation. That’s why fleet managers triage: spend the cleaning and routing budget first on the ships near a boundary, where a marginal gallon of saved fuel buys a whole letter grade, and leave the comfortably-A ships alone. Modeling each ship’s distance from its nearest boundary, which the attained-vs-required check does directly, is the first step in that triage.

The levers also interact, and not always in the operator’s favor. Sustained slow steaming saves fuel but changes combustion temperatures and load profiles in ways that affect engine cleanliness and component wear, the subject of the dedicated engine derating for slow steaming treatment. Switching to a lower-carbon fuel can mean a lower energy density per tonne, so the ship burns more tonnes of LNG or methanol to do the same work, partly offsetting the carbon-factor gain. There’s no free improvement that comes without an operational consequence, which is the honest reason CII compliance is an engineering and commercial problem rather than a box-ticking one.

Commercial consequences: charter parties and screening

The regulatory penalty for a poor CII is a corrective plan. The commercial penalty is larger and arrives faster. The first place it shows up is the charter party. In a time charter the charterer controls the two biggest CII levers, speed and route, while the owner holds the certificate and the rating. That split created an obvious problem: a charterer ordering full speed to catch a laycan can drive the owner’s CII into the red, and the owner carries the rating consequence.

BIMCO published a CII Operations Clause in November 2022 to allocate that responsibility in the contract. The clause sets a framework for the owner and charterer to agree a target CII or rating for the charter period and to define who bears the cost when the charterer’s instructions push the ship off that target. The CII clause cost-allocation tool models the money side of that split. Charter parties signed since 2023 increasingly carry the BIMCO clause or a bespoke variant, and the negotiation over the target rating is now a live commercial term, not boilerplate.

The second place is the screening file. RightShip runs a GHG rating that major charterers, especially in the dry-bulk and tanker trades, use to vet ships before fixing. A weak CII feeds a weak GHG rating, and a weak GHG rating can quietly remove a ship from a charterer’s approved list before any negotiation begins. Lenders and insurers tied to the Poseidon Principles and the Sea Cargo Charter run their own portfolio-alignment math against the IMO trajectory, so a fleet drifting toward D and E ratings can find its financing terms tightening. None of this is MARPOL enforcement; all of it is the market pricing the rating.

Criticisms of the CII design

The CII has drawn sustained criticism from operators, class societies, and academics since the first ratings landed, and the objections are specific rather than general. The deepest is the deadweight-versus-cargo distortion already noted: AER measures intensity per unit of capacity, not per unit of cargo moved, so it can reward a ship for sailing partly loaded at the right speed over a ship that filled its holds. A vessel can improve its CII by carrying less, which inverts the policy goal of moving more goods with less carbon.

The ballast-voyage penalty is the operational face of the same flaw. Many trades are structurally one-directional: a tanker hauls crude one way and returns empty, an iron-ore bulker the same. Those ballast legs burn fuel, produce no transport work the formula recognizes, and drag the annual CII down through no fault of the operator. A well-run ship on a ballast-heavy trade can score worse than a poorly run ship on a round-trip cargo route.

Idle time compounds it. A ship waiting weeks at anchor for a berth, common in congested trades, burns auxiliary fuel and sails zero distance, so its denominator stalls while its numerator keeps climbing. The voyage adjustments under MEPC.355(78) don’t cover ordinary anchor waiting, so port congestion the operator can’t control still degrades the rating. The single-year structure adds noise: CII grades a calendar year, so a ship can flip between a B and a D from one year to the next purely because its trade pattern changed, not because anything about the ship did.

The AER proxy weakness sits underneath all of these. The metric was built on data the DCS already collected, deadweight and distance, precisely to avoid imposing new cargo-measurement requirements. That choice made the regime cheap to start but baked the cargo-blindness in from day one. Industry bodies have pushed the IMO to move toward a metric based on actual transport work, a true cargo-carried denominator, in the post-2026 review, and that revision is one of the open questions the GHG-strategy review has to settle.

Limitations

CII is a screening grade, not a precise emissions audit, and the practitioner-grade caveats are worth holding in mind before any decision rests on a single letter.

The deadweight-versus-cargo gap is the first and largest. Because AER divides by deadweight times distance, not by cargo actually carried, the grade measures hull-through-water efficiency, not cargo-moving efficiency. A ship can lift its CII by carrying less or by sailing at the speed the formula likes rather than the speed the cargo needs. Read the grade as a proxy, and check the underlying tonne-miles before treating it as a measure of useful work.

The ballast-voyage penalty distorts any structurally one-directional trade. Tankers and bulkers that return empty are graded on fuel burned during legs that move no recognized cargo, so a well-operated ship on a ballast-heavy route can score below a poorly operated ship on a round-trip route. The grade reflects the trade as much as the ship.

Idle time at anchor degrades the rating without any operator fault. The voyage adjustments under MEPC.355(78) cover ice, ship-to-ship transfer, reefer electrical load, and a defined list of special cases, but not ordinary waiting for a berth. In a congested year, port queues the operator can’t control still pull the denominator flat while auxiliary fuel keeps adding to the numerator.

The AER proxy itself is the structural limit. CII was built on the deadweight-and-distance data the IMO DCS already collected, which made it cheap to launch but blind to cargo from the start. Until the post-2026 review settles on a transport-work-based metric, the grade carries that blindness, and comparisons between ships on different trades should be read with caution.

The year-on-year tightening to 2030 means today’s compliant ship isn’t tomorrow’s. The reduction factor was fixed at 5% in 2023 rising to 11% in 2026, a flat 2 points a year, but the schedule beyond 2026 is under IMO review and isn’t a number to plan against with confidence yet. A ship sitting comfortably inside a C in 2024 can drift into a D by 2026 on the same operating pattern as the required line keeps descending, and the post-2026 trajectory could steepen it further. Any multi-year fleet plan should model the moving target, not just this year’s grade. The year-on-year improvement check is built for exactly that projection.

See also

Calculators

• CII Attained: Carbon Intensity Indicator
• CII Required: target carbon intensity for the year
• CII Rating (MEPC.339(76))
• CII Attained vs Required (headroom / deficit)
• CII Corrective Trajectory
• CII Voyage Adjustment
• BIMCO CII Operations Clause cost allocation
• CII Year-on-Year Improvement

Related wiki articles

• What is AER (Annual Efficiency Ratio)?
• What is EEXI? The Energy Efficiency eXisting-ship Index explained
• What is EEDI? Energy Efficiency Design Index explained
• MARPOL Annex VI
• SEEMP Parts I, II, and III
• Slow steaming and CII
• EU ETS for shipping
• FuelEU Maritime explained
• IMO GHG strategy
• RightShip GHG rating