MARPOL Annex VI is the chapter of the IMO pollution convention that limits what ships may emit into the air. It caps sulphur and nitrogen oxides, restricts ozone depleting substances and incineration, and since 2023 it rates large ships on carbon intensity every year.
This page covers each regulation that carries an obligation, in the numbering of the revised Annex in force today, and sits alongside the other compliance guides on this site, and flags the two changes that matter most right now: the new Emission Control Areas that took effect in March 2026, and the vote scheduled for December 2026.
Two things changed recently, and one is still pending
- 1 March 2026: the Canadian Arctic and the Norwegian Sea became Emission Control Areas (IMO). The 0.10% sulphur and PM requirements bite from 1 March 2027.
- 1 August 2025: resolution MEPC.385(81) expanded the fuel oil consumption data every ship of 5,000 gross tonnage and above must report.
- 4 December 2026: the extraordinary MEPC session resumes for one day to vote again on the IMO Net-Zero Framework, after adoption was adjourned in October 2025.
The regulations that carry an obligation
Annex VI runs to more than forty regulations, but a working ship is measured against a much shorter list.
| Reg. | Subject | Applies to |
|---|---|---|
| 6 | Issue of the IAPP and IEE certificates | All ships of 400 GT and above |
| 12 | Ozone depleting substances | All ships |
| 13 | Nitrogen oxides (NOx) | Diesel engines above 130 kW |
| 14 | Sulphur oxides (SOx) and particulate matter | All ships |
| 15 | Volatile organic compounds | Tankers |
| 16 | Shipboard incineration | All ships |
| 18 | Fuel oil availability and quality | All ships |
| 22 | Attained EEDI | New ships |
| 23 | Attained EEXI | Existing ships of 400 GT and above |
| 26 | Ship Energy Efficiency Management Plan | Ships of 400 GT and above |
| 27 | Fuel oil consumption data reporting | Ships of 5,000 GT and above |
| 28 | Operational carbon intensity, the CII rating | Ships of 5,000 GT and above |
Regulation 13 caps nitrogen oxides by build date, not by fuel
NOx limits attach to the engine, and which tier applies depends on when the ship was built.
- Tier I, ships built from 2000 to 2010
- Tier II, ships built on or after 1 January 2011, worldwide
- Tier III, the strictest tier, which applies only inside a NOx Emission Control Area
This is the distinction that catches people out. A Tier II engine is compliant on the open sea and non compliant inside a NOx ECA, without anything about the ship having changed. Not every ECA covers NOx: the Mediterranean designation is for sulphur and particulate matter only.
Regulation 14 caps sulphur at 0.50% globally and 0.10% in ECAs
Since 1 January 2020, fuel oil used outside an Emission Control Area must not exceed 0.50% sulphur by mass. Inside an ECA the limit is 0.10%. That global step down is what the industry calls IMO 2020.
A ship may meet the limit by burning compliant fuel or by using an approved equivalent such as an exhaust gas cleaning system. The obligation is the emission, not the fuel. The grades, the sample thresholds and why 0.53% exists are set out here.
The ECA map is larger than most references show
Emission Control Areas in force today, per IMO and Bureau Veritas:
| Area | Controls | Since |
|---|---|---|
| Baltic Sea | SOx, and NOx for ships built from 2021 | 1996 / 2021 |
| North Sea | SOx, and NOx for ships built from 2021 | 2006 / 2021 |
| North American area | SOx, NOx, PM | 2012 |
| United States Caribbean Sea | SOx, NOx, PM | 2014 |
| Mediterranean Sea | SOx and PM | Sulphur limit from 1 May 2025 |
| Canadian Arctic | SOx, NOx, PM | In force 1 March 2026, sulphur from 1 March 2027 |
| Norwegian Sea | SOx, NOx, PM | In force 1 March 2026, sulphur from 1 March 2027 |
The Norwegian Sea area extends the existing North Sea ECA from 62° north across the Norwegian exclusive economic zone. A further North-East Atlantic ECA has been adopted and is not yet in force (DNV).
Regulation 18 is where the paperwork becomes evidence
Regulation 18 requires the supplier to hand over a Bunker Delivery Note recording what was delivered, and requires the ship to keep it for three years (IMO). The retained fuel sample has its own clock: at least twelve months.
It is the least glamorous regulation in the Annex and the one that decides most disputes, because it is the only contemporaneous record of what actually went into the tank during the bunkering operation.
The nine fields a Bunker Delivery Note must contain are set out in Appendix V, and both paper and electronic formats are acceptable.
Chapter 4 turned Annex VI from an emissions rule into a reporting rule
The energy efficiency chapter is where Annex VI stopped being only about what comes out of the funnel and started being about what you can prove on paper.
- Regulation 22, attained EEDI. A design standard for new ships
- Regulation 23, attained EEXI. A one time calculation showing an existing ship meets an equivalent standard
- Regulation 26, the SEEMP. The ship energy efficiency management plan carried on board
- Regulation 27, the Data Collection System. Mandatory annual reporting of fuel oil consumption for ships of 5,000 GT and above, expanded by MEPC.385(81) from 1 August 2025
- Regulation 28, the CII. An annual operational rating from A to E, in force since 1 January 2023 (IMO guidance on EEXI and CII). A ship rated D three years running, or E once, must submit a corrective action plan
If you are looking for regulation 22A, it no longer exists under that number. The fuel oil data collection system entered the Annex as regulation 22A in 2016. The revised Annex VI renumbered it to regulation 27, and the SEEMP requirement became regulation 26. Older circulars and training material still use the previous numbering.
The December 2026 vote decides what comes after CII
In October 2025 an extraordinary session of the MEPC met to adopt the IMO Net-Zero Framework, a set of Annex VI amendments that would price ship greenhouse gas intensity globally. The committee did not adopt it. A majority of 57 member states voted to adjourn for a year against 49 to continue (DNV).
The session resumes for a single day on 4 December 2026, immediately after MEPC 85 sits from 30 November to 3 December (Lloyd’s Register). Amendments enter into force 16 months after adoption, so even an adoption in December 2026 puts the framework no earlier than 2028.
Until that vote, the CII rating under regulation 28 remains the operative carbon instrument in Annex VI. The framework’s targets, prices and current state of negotiation are set out here.
Annex VI is now the data layer under rules that cost money
Annex VI itself carries no financial penalty for carbon intensity. A poor CII rating obliges a corrective action plan, not a payment. What changed is that European law now attaches a price to the same underlying fuel figures.
- FuelEU Maritime sets a greenhouse gas intensity limit on energy used on board, with a penalty of €2,400 per tonne of VLSFO equivalent
- EU ETS requires surrendering allowances for emissions, rising to 100% of reported emissions from 2026
- Green shipping corridors require partners with no shared parent company to agree on the same figures
The measurement obligation is old. What is new is that the same number is now read by a class society, a flag state, an EU verifier and a corridor partner, each holding their own copy.
That is the gap VesselChain is built for, and what it means in practice for a shipowner. Each bunker delivery is recorded once, at the point of delivery, signed by the accredited verifier the regulation already requires, and held identically by every party that depends on it. The regulations do not change. The reconciliation afterwards does.
Frequently asked questions
What does MARPOL Annex VI cover?
MARPOL Annex VI covers prevention of air pollution from ships. It regulates sulphur oxides, nitrogen oxides, particulate matter, ozone depleting substances, volatile organic compounds and shipboard incineration, and since 2023 it also sets mandatory energy efficiency and carbon intensity requirements.
Which ships does MARPOL Annex VI apply to?
Annex VI applies to all ships, but individual regulations have thresholds. Certification under regulation 6 and the SEEMP under regulation 26 apply from 400 gross tonnage, while fuel consumption reporting under regulation 27 and the CII rating under regulation 28 apply from 5,000 gross tonnage.
What is the current sulphur limit under MARPOL Annex VI?
0.50% by mass outside Emission Control Areas since 1 January 2020, and 0.10% inside them. Ships may comply with an approved equivalent such as an exhaust gas cleaning system instead of burning compliant fuel.
What is regulation 13 of MARPOL Annex VI?
Regulation 13 limits nitrogen oxide emissions from marine diesel engines above 130 kW. Which tier applies depends on the ship’s build date, and Tier III applies only inside a designated NOx Emission Control Area.
What is regulation 14 of MARPOL Annex VI?
Regulation 14 limits sulphur oxides and particulate matter by capping the sulphur content of fuel oil used on board, at 0.50% globally and 0.10% within Emission Control Areas.
Which areas are Emission Control Areas?
The Baltic Sea, the North Sea, the North American area, the United States Caribbean Sea area, the Mediterranean Sea, and since 1 March 2026 the Canadian Arctic and the Norwegian Sea. A North-East Atlantic area has been adopted but is not yet in force.
What happened to regulation 22A of MARPOL Annex VI?
Regulation 22A introduced the fuel oil data collection system in 2016. The revised Annex VI renumbered it as regulation 27, and the SEEMP requirement became regulation 26. Older material still refers to the previous numbering.
Has the IMO Net-Zero Framework been adopted?
No. An extraordinary MEPC session in October 2025 adjourned the adoption decision for one year by 57 votes to 49. The session resumes for one day on 4 December 2026, directly after MEPC 85. Amendments enter into force 16 months after adoption, so the framework could not apply before 2028.
