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SWITZERLAND - New Zealand ranks seventh in an environmental performance index released ahead of the World Economic Forum, an annual talkfest that attracts the most influential people in the world.

Switzerland scored top marks among 149 countries measured in six environmental areas including air pollution, water quality and how they control industrial pollution, according to the 2008 Environmental Performance Index.

Sweden came second in the ranking, compiled by environmental experts at Yale University and Columbia University, followed by Norway, Finland and Costa Rica.

The United States, dragged down by poor scores on greenhouse gas emissions and the impact of air pollution on ecosystems, placed 39th, far behind other developed states such as the United Kingdom in 14th and Japan in 21st.

"The United States' performance indicates that the next administration must not ignore the ecosystem impacts of environmental as well as agricultural, energy and water management policies," Gus Speth, dean of the Yale School of Forestry and Environmental Studies, said in a statement.

The US ranking - below Albania, Russia and Panama - was "a national disgrace", Speth said.

There wasn't a separate commentary on New Zealand in the report. Overall New Zealand scored 88.9 on the Environmental Performance Index.

It achieved 100 in the policy areas of water and sanitation. The lowest scores were for pesticide regulation, marine protected areas, biodivesity and emissions.

Australia ranked 46 with an EPI score of 79. It had low scores for water stress, pesticide regulation, climate change and emissions.