Monday, 3rd December 2012 the revised Marpol Annex V is due to enter into force on 01 January 2013.

The International Maritime Organization (IMO) Marine Environmental Protection Committee (MEPC) issued a revised Annex V to the International Convention for the Prevention of Pollution from Ships (MARPOL) under Resolution MEPC.201(62). A copy of the Resolution can be read here.
The revision reverses the historical presumption that garbage may be discharged into the sea based on the nature of the garbage and defined distances from shore and now prohibits the discharge of all types of garbage into the sea unless explicitly permitted in regulations 3, 4, 5 and 6 of the Annex. Regulation 7 allows for limited exceptions to these regulations to cover emergencies or non-routine situations.
The new regulations generally restrict discharge overboard to food wastes, identified cargo residues which are not covered by other Annexes to the Convention, animal carcasses, identified cleaning agents and additives and cargo residues entrained in hold washwater which are not harmful to the marine environment. Where possible, it is recommended that all garbage is discharged to appropriate port reception facilities.
In order to assist with the implementation of and to ensure compliance with the revised MARPOL Annex V requirements, the Marine Environmental Protection Committee have issued Resolution MEPC.219(63) - 2012 Guidelines for the Implementation of MARPOL Annex V, a copy of which can be read here.