India's contributions to meeting global mean temperature 2 °C and well below 2 °C is set to require transformational changes. A bottom up model analyses reference, intended nationally determined contributions and low-carbon scenarios assuming equal per capita cumulative emissions rights from 2011 through 2050. The cumulative CO 2 budget for India for low-carbon scenarios during this period is estimated to be around 115 Bt-CO 2 , as against 165 Bt-CO 2 for the reference scenario. To achieve such emission reduction, while maintaining high economic growth and meeting sustainable development goals, will require transformations to manifest at sub-national levels through technological transitions and strong social engineering. Our analysis shows that transitions are endemic such as shifting towards cleaner fuels, resource efficient technologies, widespread use of ICTs to balance demand-supply (e.g. smart grids), substituting demand in transport (e.g. work from home), aggressive promotion of renewables, lifestyle changes, and CCS. Modelling decarbonisation to meet the needs of increasing population and urbanization is a challenge due to the myriad and distributed nature of technologies used to provide various services, involving risks and uncertainties. The paper finally outlines specific opportunities and challenges faced to meet the increased mitigation ambition to limit the warming to 2 °C and below.