Under MARPOL Annex V, which garbage must not be deliberately discharged at sea?
Short answer
Plastics
Annex V starts from a prohibition and does not provide a routine discharge exception for plastics. Food waste has narrow conditional exceptions; cardboard and metal are also not made dischargeable by distance. Bring them ashore. Revise the decision table in Garbage Disposal.
Quick check
Under MARPOL Annex V, which garbage must not be deliberately discharged at sea?