What is the purpose/objective of designating special areas under various Annexes of MARPOL convention? What are PSSAs and how are they different from designated special areas.

Purpose/objective of designating special areas:

A special area is a sea area where, for recognised technical reasons relating to its oceanographical and ecological condition and the particular character of its traffic, the adoption of special mandatory methods for the prevention of sea pollution is required. The purpose is to provide a higher level of protection to environmentally sensitive or heavily trafficked sea areas by imposing stricter discharge/emission controls than apply generally. Within a special area:

• The discharge of the relevant pollutant (oil, noxious liquid substances, garbage, sewage, or air emissions) is prohibited or more strictly limited (e.g. no discharge of oil/garbage, or stricter distance/quantity limits).
• Ports in the special area must provide adequate reception facilities.
• The special-area status is defined in the relevant MARPOL Annex (I - oil, II - NLS, IV - sewage, V - garbage, VI - air/emission control areas).

Examples: the Mediterranean, Baltic, Black Sea, Red Sea, Gulfs area, Gulf of Aden, Antarctic, North West European waters (Annex I); the Mediterranean, Baltic, Black Sea, Red Sea, Gulfs, North Sea, Wider Caribbean, Antarctic (Annex V); the Baltic and North Sea (Annex IV); the North American and US Caribbean ECAs and the Baltic/North Sea NECAs (Annex VI).

PSSAs and how they differ from special areas:

A Particularly Sensitive Sea Area (PSSA) is an area that needs special protection through action by IMO because of its significance for recognised ecological or socio-economic or scientific reasons and which may be vulnerable to damage by international shipping activities. It is designated by the MEPC after meeting the criteria (ecological, socio-economic/cultural, scientific/educational) and is protected by associated protective measures (routing measures such as areas to be avoided, traffic separation, mandatory reporting, and/or discharge restrictions).

Differences:

• Basis: A special area is based on the oceanographical/ecological condition and traffic character, and is defined in a MARPOL Annex with specific discharge prohibitions; a PSSA is based on the area's ecological/socio-economic/scientific significance and vulnerability to shipping, and is designated by a separate IMO process (MEPC resolution).
• Measures: A special area imposes specific discharge/emission restrictions (a MARPOL regulatory measure); a PSSA is protected by associated protective measures which may include routing measures (under COLREGS/SOLAS) and/or discharge restrictions (which may be achieved by also designating it a special area or by other measures).
• Overlap: A PSSA may also be a special area (e.g. the Great Barrier Reef is a PSSA and the area has special-area-like protection), but a PSSA is a broader concept that can use routing and other measures in addition to discharge controls, whereas a special area is specifically a MARPOL discharge-control designation.
• Process: Special areas are adopted by amendment to a MARPOL Annex; PSSAs are designated by the MEPC after a proposal by the coastal State(s) and the adoption of the associated protective measures.