Solar Rooftops in Indias Smart Cities: A Pathway to Sustainable Urban Green Energy Transition

India's Smart Cities Mission (SCM), encompassing 100 cities since 2015, integrates ICT with sustainable infrastructure to address rapid urbanization (projected 600 million urban dwellers by 2036; MoHUA, 2023). Solar rooftops emerge as a cornerstone of green energy, aligning with India's 500 GW non-fossil capacity target by 2030 (NDC, 2022). Rapid urbanization, rising electricity demand, and ambitious national renewable energy targets have elevated rooftop solar energy as a strategic lever for sustainable urban decarbonization in India. This paper examines the role of solar rooftops within the Smart Cities Mission as an enabling pathway towards a green energy transition. Also evaluates solar rooftop deployment in Indian smart cities, focusing on techno-economic feasibility, policy efficacy, and sustainability impacts Drawing on national policy frameworks, recent deployment data, and illustrative smart-city case studies, the study analyses drivers, technical and institutional enablers, socioeconomic impacts, barriers, and practical recommendations for scaling rooftop solar across urban India. We find that grid-connected rooftop solar (RTS) can substantially contribute to urban decarbonization, energy access, and distributed energy resilience when supported by integrated city-level planning, streamlined regulatory processes, financing innovations, and capacity building. Policy synergies between central schemes (e.g., Grid Connected Rooftop Solar Programme Phase II, PM Surya Ghar) and city-level Smart Cities initiatives have produced promising pilot outcomes, yet persistent challenges—landlord/tenant split incentives, distribution network constraints, financing gaps, and data/monitoring shortfalls—need targeted interventions. The paper concludes with a city-action framework and policy recommendations to scale RTS in smart cities to meet both climate and urban development objectives.