The study, which is conducted by Yale University's Center for Environmental Law and Policy and Columbia University, ranks 132 countries on 22 performance indicators in 10 policy categories: environmental health, water (effects on human health), air pollution (effects on human health) air pollution (ecosystem effects), water resources (ecosystem effects) biodiversity and habitat, forests, fisheries, agriculture and climate change.

Switzerland (with an EPI score of 76.69) leads the world in addressing pollution control and natural resource management challenges. Its top ranking on the 2012 EPI is in mostly due to its high performance in air pollution control. Latvia (70.37), Norway (69.92), Luxembourg (69.2), and Costa Rica (69.03) round out the top five positions in the 2012 EPI.

The results show that it is possible for some middle-income countries, such as Latvia (per capita GDP $12,938) and Costa Rica (per capita GDP $10,238) to achieve impressive environmental outcomes. This also suggests that income alone is not a sole determinant of environmental performance – policy choices and good governance also matter.

At the low end of the 2012 EPI rankings are South Africa (34.55), Kazakhstan (32.94), Uzbekistan (32.24), Turkmenistan (31.75), and Iraq (25.32). These countries have water scarcity and face significant sustainability challenges; the last three are also known for weak governance.

Environmental Performance Index– Ranking & Scores

Top performers

1 Switzerland

2 Latvia

3 Norway

4 Luxembourg

5 Costa Rica

6 France 19

7 Austria

8 Italy

9 United Kingdom

and Sweden

11 Germany

12 Slovakia

13 Iceland

14 New Zealand

15 Albania

16 Netherlands

17 Lithuania

18 Czech Republic

19 Finland

20 Croatia

Worst performers

120 Pakistan

121 Tajikistan

122 Eritrea

123 Libya

124 Bosnia & Herzegovina

125 India

126 Kuwait

127 Yemen

128 South Africa

129 Kazakhstan

130 Uzbekistan

131 Turkmenistan

132 Iraq