From its dazzling coasts and pristine jungles to its steady and lucrative stream of ecotourists, Costa Rica has long been considered the iconic green nation. Nearly one-quarter of the country’s territory lies in national protected areas. More than 90% of its energy comes from local renewable-energy sources. The country also has been a policy innovator, boasting the world’s first payment-for-environmental-services program, Latin America’s first sport hunting ban and the developing world’s first carbon-trading system.

But in the 2014 Environmental Performance Index (EPI), released Jan. 25 by Yale and Columbia universities, the portrayal of Costa Rica is not so sunny. The biennial EPI ranks Costa Rica 54th of 178 nations on its success in addressing a composite of environmental issues including air quality, wastewater treatment and carbon emissions. That is a steep fall from its standing in 2010 when it ranked third in world and from 2012, when it placed fifth.