MARPOL

MARPOL (from “marine pollution”) is the IMO’s International Convention for the Prevention of Pollution from Ships, adopted in 1973 and modified by its 1978 Protocol — hence the common designation MARPOL 73/78. It is organized in six annexes:

• Annex I — oil (this annex drove the phase-out of single-hull tankers)
• Annex II — noxious liquid substances carried in bulk
• Annex III — harmful substances in packaged form
• Annex IV — sewage
• Annex V — garbage, including a general prohibition on plastic disposal at sea
• Annex VI — air pollution, including SOx and NOx limits and, since 2023, the carbon-intensity measures EEXI and CII

Annex VI has been the most consequential in recent years: the global 0.5% sulphur cap (“IMO 2020”) reshaped fuel markets, Emission Control Areas impose a stricter 0.1% limit in designated waters, and the IMO’s greenhouse-gas strategy is progressively adding carbon regulation on top.

Special Areas under the various annexes (such as the Mediterranean and Baltic) carry stricter discharge rules, and violations are prosecuted vigorously — “magic pipe” oily-water cases in the United States regularly produce multi-million-dollar criminal penalties.