Under Annex I, oil discharge is forbidden for which ships?

• A. All ships over 400 gross tonnes and tankers over 150 gross tonnes
• B. All ships over 1000 gross tonnes
• C. All ships
• D. Only fishing vessels

Answer: (A)

MARPOL Annex I aims to prevent sea pollution by restricting oil discharges from ships, with stricter rules for larger vessels. The blanket prohibition targets ships that are large enough to pose a greater risk: ships over 400 gross tonnes and all tankers over 150 gross tonnes may not discharge oil into the sea at all, except under very specific, tightly controlled conditions. This threshold reflects the higher potential impact of larger ships and ensures tighter protection where it matters most. Smaller vessels don’t fall under this universal ban, as they may discharge under permitted circumstances, but the rule clearly sets the prohibition for those size categories.