This chapter determines the role, both theoretical and empirical, of urban areas in contributing to national greenhouse gas (GHG) emissions, with India being the case in point. This essentially mandates a comprehensive review of existing footprint methodologies, inventories and tools that are used to quantify GHG emissions. In this regard, there is a growing interest in the carbon footprint of cities and geopolitical regions. Since the mid-1990s and the early 21st century, efforts to develop GHG inventories (at the project, national, regional or international levels) have been elevated from an almost purely (and at times obscure) technical matter to a critical and central component of any system or policy that aims to mitigate the effects of climate change. In addition to the standard methodologies promoted by the industry, scientific community and international or multilateral organizations, the chapter deliberates into the background of the scientific methods on which these methodologies are based.