Evaluating the potential or actual sustainability of various project options from an Environmental Impact Assessment (EIA) is a long cherished goal. However, the goal continues to be somewhat unfulfilled because of the underlying problem of how to assess the sustainability of a project through a rational approach rather than subjective judgement. Improvements in rational approaches to evaluate sustainability from EIAs recently have shown promise. However, the continuing lack of a fundamental and consistent definition of sustainability applied to EIAs continues to be evident. Consequently, the interpretation of sustainability from EIA tends to be case-specific, and unable to be comparable to other options or similar projects. Based on a Rapid Impact Assessment Matrix (RIAM) assessment for municipal solid waste disposal options in Varanasi, India, the paper applies a mathematical model of sustainability to determine whether the options are potentially sustainable or unsustainable, and if deemed as sustainable, determine the level and nature of sustainability. The results indicate that out of the five options evaluated, Gasification was the most promising sustainability option with an obtained S-value of 0.069, which indicated very weak sustainability. However, based on the results for Gasification obtained, there needs to be significant improvements in the environmental and social aspects of the project, which in turn could lead to an improvement in the obtained indicated S-value. (C) 2013 Elsevier B.V. All rights reserved.