The Yale University and Columbia University in collaboration with the World Economic Forum gather information to create The Environmental Performance Index (EPI).
The data covers the environmental health and ecosystem vitality of 180 countries.
Air, water quality and heavy metal exposure are part of the metrics used to measure the environmental health.
And biodiversity & habit, forest, fisheries, climate & energy, air pollution, water source and agricultura are the seven metrics used to score the ecosystem vitality of each country. See following picture
Switzerland leads the top of the list with an EPI score of 87.42 follows by France - 83.95, Denmark - 81.60 and Malta - 80.9.
As a region, Europe is the leader on environmental performance taking all the 15 first position on the ranking.
At the bottom of the ranking Burindi, 27.43, Bangladesh, 29.56, Dem Rep Congo, 30.41 and India 30.57 leading for their bad score on air quality, protecting biodiversity, and reducing GHG emissions.
As a region Africa leads the bottom of EPI ranking.
Other countries like The United States places the 27th in the 2018 EPI, because of it bad performance deforestation, 8.84, and GHG emissions 45.81. It gets nearly one of the last positions for the industrialized nations.
China and India rank 120th and 177th respectively, the economy growth hasn't consider the environment factor. They have really bad air condition India with 5.75, and China with 14.39.