We have moved almost entirely from the Environmental Sustainability Index (ESI) approach to the Environmental Performance Index (EPI) approach (see http://epi.yale.edu), which has proven to be more useful for the policy community.  We recognize that there is a community of researchers with an
interest in the continuation of the ESI, but at present we have no definite plans to update it.  On the other hand, the raw indicator data for the EPI could easily be used to construct ESI-type indices.