The EWI is an broad measure of the state of the environment, with a fuller and more systematic treatment of national environmental conditions than other global indices such as the Ecological Footprint and the Environmental Sustainability Index. It is the average of:
- Land. How well a country conserves the diversity of its natural land ecosystems and maintains the quality of the ecosystems that it develops.
- Water. River conversion by dams. The water quality of drainage basins. Water withdrawal as a percentage of the national supply from precipitation. Inadequate data prevented coverage of the sea.
- Water Air. Emissions of greenhouse gases and ozone depleting substances to the global atmosphere . City air quality.
- Water Species and genes. How well a country conserves its wild species of mammals, birds, amphibians, reptiles, and higher plants, and the variety of its domesticated livestock breeds .
- Water Resource use. How much energy a country consumes. The demands its agriculture, fishing, and timber sectors place on resources.