In January 2000, the Yale Center for Environmental Law and Policy (YCELP) and CIESIN launched the Pilot 2000 Environmental Sustainability Index (ESI), and a year later they released the first full report with league tables, the 2001 ESI. Transitioning to an Environmental Performance Index (EPI) in 2006, they have been releasing the biennial report ever since. CIESIN has been a strong partner in the effort, focusing first on data processing and methods, and transitioning over the years to areas of data innovation, including the incorporation of remote sensing-derived indicators, and now AI-enabled data. CIESIN was part of efforts to develop the first Water Quality Index (incorporated as an indicator in the 2005 ESI), and contributed to the development of innovative air quality and wastewater treatment indicators (later adopted as SDG 6.3). CIESIN recently set up an archive of all ESI & EPI releases on the Harvard Dataverse.
The 2026 EPI represents the culmination of 25 years of refinements in methods and data inputs. For more information on results, read the State of the Planet blog post.
To see the 2026 EPI results, visit: https://epi.yale.edu/
