Highest "Clean Waters" score in the Ocean Health Index

The highest national score in the "clean waters" category of the annual Ocean Health Index is held by Canada, which had an score of 84 out of 100 in the 2019 edition of the index. Technically, Canada places 13th in the rankings, but the entries above it are all uninhabited island groups or external territories of other countries (such as Greenland or the Falkland Islands).

The Ocean Health index (OHI) is a set of global rankings compiled and updated as a collaboration between Conservation International and the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara. The experts involved with the OHI give each country a score for their performance in certain key areas, which include things like marine resource allocation, pollution levels, biodiversity and the strength of coastal economies. The overall score is then calculated as a weighted average of these scores. The first edition of the OHI was published in 2015.