The Environmental Performance Index, developed by Columbia and Yale Universities, ranks the environmental performance of 140 countries based on 25 categories ranging from air and water quality to biodiversity and the use of pesticides. This list looks at the top countries in each of six world regions and the ways in which each excel, as well as areas where the countries lag their peers.
The declining health of Mother Earth has drawn growing attention over the last two decades, with countries coming together to fight a range of environmental threats, from declining fishing stocks to global warming.
Witness the Kyoto Protocol, the first widely adopted set of environmental protection guidelines, which emerged during the 1990s and took effect in 2005. Kyoto led to the development of the first large-scale emissions trading market, Europe's Greenhouse Gas Emission Trading Scheme, which puts caps on carbon dioxide pollution. A similar carbon market, the Regional Greenhouse Gas Initiative, began operating at the start of this year in 10 Eastern U.S. states.
In spite of nearly universal support for a cleaner globe (the U.S. was one of only a few countries that failed to adopt Kyoto), it's mainly the rich nations that enjoy pristine environments, according to the Environmental Performance Index (EPI). Columbia University's Center for International Earth Science Information Network and Yale University's Center for Environmental Law and Policy developed the index to highlight the cleanest countries, and give laggards the opportunity to benchmark efforts to improve their own environments and the health of their citizens.
In Pictures: The World's Cleanest Countries
Switzerland tops the list with an overall EPI score of 95.5 out of 100, while European countries account for 14 of the top 20 environmental performers. Europe has the infrastructure to provide clean drinking water and treat waste water, lowering the likelihood that Europeans will suffer from waterborne disease. Europe scores consistently well in EPI's environmental health ranking, which measures the effects of pollution on human health.