Energy is a key input for the socio-economic development of a country, particularly for countries like India. Hence, it is important to holistically and objectively understand and assess the country’s energy sector, so that policies and interventions can be appropriately prioritized to further the country’s development. This report develops a comprehensive energy sector assessment index for such an assessment of India's energy sector, by considering not only energy demand and supply but also the relationship and impacts of the energy sector on society, environment and the economy. The index should be periodically computed to understand the energy sector and trends within it. As a beginning, this report presents the energy sector assessment index for India for 2011-12. This assessment throws up some interesting insights.