MARPOL Annex VI, regulations 26 & 28 incorporates requirements on ships of 5000 GT and above of certain types to amend their Ship Energy Efficiency Management Plans (SEEMP) with a new mandatory part III, and to calculate their “required annual operational CII” and their “attained CII” for each year...
https://www.hellenicshippingnews.com/with-cii-now-in-force-should-my-t-c-mention-cii/