There are approximately 116 straits used for international navigation around the world. Some of them are important international maritime chokepoints, namely the Dover Strait, Hormuz Strait, Straits of Malacca and Singapore and the Russian straits across the Northeast Arctic Passage. Due to the high number of navigational traffic going through these straits, vessel-source pollution is endemic in these waters. This article examines the applicable international legal framework on protection of the marine environment of straits used for international navigation such as Part XII of the United Nations Convention on the Law of the Sea and other related legal measures like International Maritime Organization conventions on protection of the marine environment. This article concludes by stating that the present framework is not sufficient in properly balancing two vital interests in the maritime world – protection of the marine environment vis-à-vis shipping.

I. Introduction
 II. Part XII of the UNCLOS
  A. Port State Jurisdiction
  B. Coastal State Jurisdiction
  C. Flag State Jurisdiction
 III. Legal Effect of Article 233 of the UNCLOS
  A. Interpretation of Article 233
  B. The Application of Article 233 to State Practices
  C. Defining ‘Major Damage’
 IV. Conclusion

• Hazmi Rusli(Faculty of Syariah and Law, Universiti Sains Islam Malaysia.)
• R. Dremliuga(School of Law, Far Eastern Federal University)
• Wan I. Talaat(Institute of Environment and Oceanography, University Malaysia Terengganu, Malaysia)