Cities are the key to India’s future, standing at a pivotal moment of transformation. Home to around 480 million people[1] India’s urban population is projected to approach one billion by 2050. Indian cities face mounting exposure to climate-related risks – from intense rainfall and urban flooding to extreme heat – yet they are also where the most practical solutions to these challenges can be applied. A major part of the problem lies in the built environment; energy use in buildings and stationary sources accounts for somewhere between 68% and 75% of total urban greenhouse gas emissions, as revealed in the Paris-aligned climate action plans of Bengaluru[2] and Mumbai[3]. Within this, municipally owned buildings such as government offices, schools, hospitals, and community centres represent a strategic starting point; cities control these assets directly, aggregate demand, and demonstrate market feasibility.
Rooftop solar serves as the primary engine for this transformation
As India accelerates toward its 500 GW non-fossil fuel target[4] – distributed solar on municipal rooftops will be essential for decarbonizing Indian cities. Despite significant potential, adoption remains limited due to a set of persistent barriers[5] such as fragmentation of assets; buildings with small electrical loads, high transaction costs, and no clear accountability, financial constraints: most Urban Local Bodies (ULBs) lack dedicated capital budgets for energy investments, and often end up deferring high-return projects and most critically, institutional challenges such as fragmented data across departments, delays in approvals with utilities, and limited in-house capacity for procurement and monitoring. These “soft barriers” frequently outweigh technical feasibility and stall implementation.
Emerging city experiences from Bengaluru, Chennai and Nashik point to clear pathways to overcome these constraints. A key strategy is demand-aggregation; bundling multiple buildings into a single pipeline to improve project scale and bankability. Bengaluru’s solar roadmap demonstrates this approach by utilizing geospatial mapping and drone imagery across 742 municipal buildings; the city identified a “high-priority” cluster of 80 buildings that represent 87% of the total sanctioned load. By aggregating this demand, the city can pivot from a CAPEX-heavy model that is one where the municipal corporation has to invest its own upfront capital to install rooftop solar systems to a RESCO (Renewable Energy Service Company) pathway where no upfront investment for the city is required and is critical to achieve economies of scale). The results are compelling: a potential 6.19 MW capacity with zero upfront cost to the government, generating nearly ₹58 crore in lifetime savings. In the BESCOM jurisdiction alone, there are over 40,000 government buildings with a cumulative potential of 452 MW. Bengaluru is not alone. Pune Municipal Corporation is deploying the RESCO model across 34 municipal buildings with a target of 1.2 MW installed capacity.
Efficiency first: unlocking the existing stock
Solar alone is insufficient, and efficiency must come first, reducing demand before offsetting it with generation. While new buildings can embed this from the outset, the harder challenge is existing stock: most Indian municipal buildings predate energy standards and suffer from poor sealing, inadequate insulation, outdated lighting, and inefficient cooling equipment.
Retrofitting these buildings, replacing lighting with LED systems, upgrading HVAC equipment, improving window glazing and wall insulation, installing smart metering and building management systems can reduce energy consumption by 30 to 50% in many cases[6]. The challenge is that retrofitting requires upfront capital, and ULBs typically lack both the capital and the technical capacity to design and implement retrofit programmes at scale.
C40’s work in Maharashtra has identified several pathways to address this. Energy Performance Contracting enables private companies to finance and implement energy retrofits, with repayment tied to verified energy savings rather than upfront municipal spending. What distinguishes this approach is its institutional grounding. Mumbai’s example explicitly links financing mechanisms to governance structures, a proposed Climate Budget Steering Cell coordinating across environment, engineering, and finance departments and to a Measurement, Reporting and Verification framework that gives lenders and ESCOs the performance data they need to price risk confidently. For urban local bodies across the Global South facing similar fiscal constraints, this integrated model offers a replicable template.
Cool roofing and passive design is often the first line of defence
In 2026 so far, India is experiencing widespread heatwaves with parts of the country reporting[7] temperatures above 40 degrees. For municipal buildings, many of which are older, poorly insulated concrete structures with dark, heat-absorbing roofs, this translates into higher cooling loads, higher electricity bills, and worse conditions for occupants.
While active cooling is energy-intensive, passive cooling is becoming the “low-hanging fruit” of urban resilience. Learnings from C40’s work in Amravati and Chandrapur show[8] Solar Reflective Index (SRI) coatings (typically in the range of ₹15 to ₹40 per square foot) and green roofing can reduce indoor temperatures by 3–6°C. Yet adoption in India’s municipal building stock remains patchy. By reducing thermal stress on a building, we lower the initial energy requirement, making the eventual solar transition more affordable and the equipment more durable.
Behavioural Energy Efficiency; the invisible lever
Finally, the most overlooked yet critical lever for change is behavioural energy efficiency. A meaningful share of energy waste is behavioural and therefore addressable at very low cost. Lights left on in unoccupied rooms, air conditioning systems set to temperatures far below comfort requirements, equipment left on standby overnight, and procurement decisions made without any consideration of energy consumption. C40’s engagements with Navi Mumbai and Thane[9] shows that behaviour change can deliver 5 to 10% reductions in building energy consumption without any capital investment, simply through awareness campaigns, occupancy-linked automation, energy dashboards visible to building users, and the designation of energy monitors within each building.
Integrated foundation for decarbonisation
The most consequential lesson emerging from C40’s work across Indian cities is that decarbonisation interventions achieve their greatest impact when structurally integrated rather than siloed across departments, as coordinated building retrofits consistently outperform a decade of disconnected incremental upgrades in both climate and fiscal terms. This integration is especially urgent now, since India’s historic construction wave means today’s design choices will lock in energy trajectories for the next 30 to 50 years.
For India’s cities and the hundreds of millions of people who will inhabit them over a warming century, the cost of delay is not abstract. It is measured in unpaid energy bills, in productivity lost to heat, and in buildings that were never designed to withstand the climate they now face. The window to get this right remains open. It will not do so indefinitely.
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Author Bio:
Naim Keruwala is the Regional Director for South & West Asia at C40 Cities Climate Leadership Group; a global network of 97 cities helping cities move faster and go further on climate action. Prior to joining C40, he led the Government of India’s CITIIS program as a Program Director at the National Institute of Urban Affairs (NIUA), overseeing a US$500 million blended finance portfolio on sustainable urban development. Naim is a member of the advisory board of the Symbiosis Centre for Urban Studies, a Salzburg Global Fellow, an Associate Fellow of the Royal Commonwealth Society, an alumnus of the U.S. State Department’s International Visitor Leadership Program (IVLP).
[1] India Population (2026) – Worldometer
[2] climate action and resilience plan for bengaluru
[3] Mumbai Climate Action Plan summary
[4] 500GW Nonfossil Fuel Target | Government of India | Ministry of Power
[5] Needs Gap Assessment for Rooftop Solar in Chennai
[6] Roadmaps for net zero and behavioural energy efficiency in municipal buildings of Maharashtra cities
[7] Severe Heatwave grips India with 95 of World’s Hottest Cities reportedly located in country | DD News On Air
[8] Scaling urban heat resilience: Policy-driven and community-led heat action in Amravati and Chandrapur
[9] Roadmaps for net zero and behavioural energy efficiency in municipal buildings of Maharashtra cities
