Denmark came second, with 9.4 points, followed by Switzerland on 8.8 points. At the bottom of the list was the United States on 2.2 points, well behind Turkey and Mexico in 28th and 29th places respectively.
The rankings were based on an index that considers countries' performance across a range of indicators, including emissions, biological diversity, energy consumption and participation in international treaties.
In social sustainability, the index considers health, living standards, equality and education.
Sweden was ranked top in social sustainability and
second-best in environmental development. It received high marks for
its work in implementing the Kyoto Treaty on greenhouse gases,
environmental policy in general, and equality.