The Environmental Performance Index (EPI) is a biennial ranking of how well countries perform on high-priority environmental issues, including air quality, climate change and energy, forests and fisheries. The 2014 EPI is the tenth iteration of the leading global environmental metric. It is a collaboration between Yale and Columbia universities and the World Economic Forum. It is supported by the Samuel Family Foundation and the McCall McBain Foundation. Learn more at www.epi.yale.edu.