The International Maritime Organization (IMO) is a United Nations specialized agency that focuses on the safety of ships and the pollution that is caused by them in the seas. While it focuses on safety, security, and environmental performance it also covers all aspects of international shipping (including ship design, construction, equipment, manning, operation and disposal) to ensure the smooth running of this sector. The Marine Environment Protection Centre 76 conducted a series of meetings from 10 to 17 of June 2021 where they adopted new mandatory measures into the Annex 6. The revised Annex requires ships to calculate the EEXI and establish a CII rating.

The CII – Carbon Intensity Indicator measures the amount of carbon emissions that a ship gives out annually. It will apply to ships with 5000 gross tonnage and above. The ships will get a rating of their efficiency on the scale of A to E based on which their efficiency will be defined. A to C is a good scale to be in, whereas if the ship surpasses and gets a rating of D or E for three consecutive years, it is required to take the required measures to move up.