"Costa Rica is proud to be a global leader in environmental conservation," said President Oscar Arias.

In Latin America, Colombia came second after Costa Rica.

The United States, meanwhile, came 39th among the index's 149 countries, with the United Kingdom scoring at 14.

Back in Costa Rica, a separate report also brought good news to the environment. The country has cut its imports of ozone depleting gases by 71.5%, the Environment Ministry said. In 2004 the country imported 105 tons of chlorofluorocarbons (CFCs), while in 2007, the amount was just 30 tons, according to newswire ACAN-EFE.

Industries have also reduced the purchase of harmful agricultural chemicals such as methyl bromide, typically used by melon growers to control a wide variety of pests. Imports of that chemical dropped from 1,070 tons in 1999 to 400 last year, thanks to a national phase-out program.