The 2020 Environmental Performance Index (EPI) scores 180 countries on 32 performance indicators across 11 issue categories related to environmental health and ecosystem vitality. The 2020 EPI is a composite index. The EPI researchers begin by gathering data on 32 individual metrics of environmental performance. These metrics are aggregated into a hierarchy beginning with 11 issue categories: Air Quality, Sanitation and Drinking Water, Heavy Metals, Waste Management, Biodiversity and Habitat, Ecosystem Services, Fisheries, Climate Change, Pollution Emissions, Water Resources, and Agriculture.

These issue categories are then combined into 2 policy objectives, Environmental Health and Ecosystem Vitality, and then finally consolidated into the overall EPI. To allow for meaningful comparisons, before aggregation the EPI researchers construct scores for each of the 32 indicators, placing them onto a common scale where 0 indicates worst performance and 100 indicates best performance. How far a country is from achieving international targets of sustainability determines its placement on this scale.

Note: The EPI scores are not comparable over time, therefore, this dataset only includes the EPI scores from the latest release.