Environmental Performance Index 2010
The 2010 Environmental Performance Index (EPI) ranks 163 countries on 25 performance indicators tracked across ten policy categories covering both environmental public health and ecosystem vitality

There’s a slideshow of the top 10 in the Forbes article here. Iceland comes first. You might go “huh?” with all the volcanic ash, but the study does not score natural disasters. That makes sense. Sweden is 4th, and I was pleasantly surprised to see Mauritius holding its own there in the list at number 6. Great!