What is an environmental sustainability index (ESI)?

An environmental sustainability index (ESI) is indeed a measure of a country's environmental sustainability. It provides a quantitative assessment of how well a country is managing its environmental resources and impacts. The ESI takes into account various indicators related to environmental health, the quality of ecosystems, and the social and institutional capacity to promote sustainability. This metric helps to compare the sustainability practices of different countries, guiding policymakers and stakeholders in improving environmental management.

The other options do not accurately define what an ESI is. While economic growth, education quality, and renewable energy sources are important aspects of a country's overall development and sustainability efforts, they are not the primary focus of the environmental sustainability index. The ESI is specifically dedicated to evaluating environmental practices and impacts rather than broader economic or educational indicators.