Bhopal: Concrete and asphalt trap daytime heat, worsening the urban heat island effect in dense neighborhoods.
Deepak Sankat; Wikimedia Commons
Every summer, India's cities face a growing challenge. Heatwaves are becoming longer, more frequent and more intense. Temperatures crossing 45°C are no longer unusual, while dense urban neighbourhoods often feel even hotter because of the urban heat island effect where concrete, asphalt and built structures absorb and retain heat throughout the day.
Against this backdrop, Bhopal has emerged as an unlikely pioneer. On World Environment Day 2026, the Bhopal Smart City Development Corporation Limited (BSCDCL), in collaboration with The Energy and Resources Institute (TERI) and the Smart Surfaces Coalition (SSC), released what is being described as the first citywide assessment in India of how urban surfaces can be redesigned to reduce temperatures at scale. According to the study, widespread adoption of “smart surfaces” could lower peak summer temperatures in parts of Bhopal by as much as 2.8°C and reduce citywide temperatures by up to 3°C.
The findings are significant because they challenge the assumption that air conditioning is the primary solution to urban heat. Instead, the study argues that the very surfaces that make up cities like roofs, roads, pavements, trees, open spaces and solar installations, can be transformed into a powerful cooling system.
Heat reflective and energy saving paint
The report, titled Bhopal Citywide Smart Surfaces for Cost-Effective Cooling and Resilience, was supported by the MacArthur Foundation and developed using advanced satellite data, urban morphology analysis and temperature modelling. According to the project partners, it is the first effort in India to quantify the cooling benefits of smart surfaces at a citywide scale.
The science behind urban heat is well established. Most urban surfaces have low reflectivity, meaning they absorb rather than reflect solar radiation. Dark roofs, asphalt roads and concrete structures store heat during the day and release it slowly at night.
The Bhopal study found that the city's average albedo, or surface reflectivity, is only 0.165. This means urban surfaces absorb nearly 83 percent of incoming solar energy, contributing significantly to local warming. Researchers mapped Bhopal's 463 square kilometre municipal area using high-resolution satellite imagery and detailed surface analysis, producing heat maps with resolutions ranging from one to thirty metres.
The results revealed that heat exposure is not evenly distributed across the city. Wealthier neighbourhoods generally benefit from larger plots, more vegetation and better ventilation. In contrast, densely populated low-income settlements often have little green cover and are built with materials that trap heat.
As a result, lower-income neighbourhoods can be 5 to 6°C hotter than wealthier parts of the city during summer. This makes urban heat not only an environmental issue but also a social equity challenge. The people most exposed to dangerous temperatures are often those with the least access to cooling technologies.
The implications extend beyond comfort. Extreme heat affects labour productivity, increases electricity demand, worsens air pollution, disrupts learning in schools and contributes to illness and premature mortality. The World Health Organization and numerous public health studies have repeatedly identified heat stress as one of the most serious climate-related risks facing urban populations. India's rapidly urbanising landscape means that these challenges will only intensify unless cities adopt proactive cooling strategies.
The study arrives at a time when air-conditioning demand is expected to surge dramatically. According to figures cited in the report, the International Energy Agency projects a more than tenfold increase in air-conditioning units in India by 2050, reaching around one billion units. Yet even with such growth, a substantial proportion of Indians would still lack access to cooling. Moreover, air conditioners release waste heat into surrounding areas, potentially increasing outdoor temperatures by up to 2°C in dense urban environments.
This creates a paradox. Air conditioning cools indoor spaces for those who can afford it while making outdoor environments hotter for everyone else. Smart surfaces offer a different pathway. The concept combines several interventions, including cool roofs, reflective pavements, permeable surfaces, urban greening, tree planting and rooftop solar installations. These measures increase the reflectivity and thermal performance of urban surfaces, reducing heat absorption and lowering ambient temperatures.
For Bhopal, the modelling indicates that citywide implementation could generate substantial cooling benefits. Peak summer temperatures in the dense urban core could decline by as much as 2.8°C. Such reductions may appear modest, but in heat-risk management they are extremely significant. Epidemiological studies show that even a one-degree reduction during extreme heat events can reduce heat-related illnesses and deaths.
The economic case appears equally compelling. The study estimates that smart surface interventions would generate benefits worth 3.5 times their costs over a ten-year period. Among the measures assessed, tree planting produced the highest benefit-cost ratio at approximately 7:1, while cool roofs and rooftop solar installations delivered benefit-cost ratios of about 5:1.
The climate benefits are also notable. According to the analysis, implementing the recommended interventions could reduce greenhouse gas emissions by around 11 million tonnes of carbon dioxide equivalent by 2046.
Perhaps most importantly, the study notes that several benefits were not fully incorporated into the economic calculations. These include improved worker productivity, lower healthcare costs, reduced mortality, enhanced tourism attractiveness and improved educational outcomes from cooler classrooms. More than fifty schools could benefit from reduced indoor temperatures, creating healthier learning environments for children.
Bhopal's experience offers valuable lessons for urban policymakers across India. However, replicating these benefits will require more than isolated pilot projects.
The findings from Bhopal show that reducing urban heat requires cooling to become a core part of city planning rather than an afterthought. Building regulations in most Indian cities continue to focus mainly on structural safety and land use. To make cities more resilient to rising temperatures, development rules need to include measures such as reflective roofs, minimum tree cover, and heat-resilient urban design.
State governments can support this shift by creating dedicated urban cooling missions linked to existing climate adaptation and Smart City programmes. The Bhopal study found that cooling interventions generate economic benefits that are greater than their costs, making a strong case for public investment and concessional financing.
Cities also need better information to guide action. Municipal corporations should prepare detailed heat vulnerability maps, similar to those developed for Bhopal, to identify neighbourhoods most at risk. While many Heat Action Plans focus on responding to heat emergencies, heat mapping can help cities prevent impacts by directing investments to the hottest and most vulnerable areas.
Several proven solutions can be implemented immediately. Cool roof programmes deserve rapid expansion, building on successful experiences in cities such as Ahmedabad and Hyderabad. The Bhopal study adds to growing global evidence that reflective roofs are among the most cost-effective ways to reduce urban temperatures.
Urban trees should receive equal priority. The study found that tree planting delivers exceptionally high returns because trees provide multiple benefits. In addition to cooling neighbourhoods, they improve air quality, absorb stormwater, support biodiversity, and enhance public well-being. Yet many cities continue to lose mature trees to infrastructure projects without adequate replacement.
Schools present another important opportunity. The study suggests that cool roofs, reflective surfaces, and shaded outdoor spaces can be incorporated into school infrastructure as standard design features, improving both learning environments and public health outcomes.
The study also highlights the need to connect cooling strategies with energy policy. Rooftop solar systems were identified as an important intervention. When combined with cool roofs, solar installations can lower indoor temperatures, reduce electricity bills, and cut carbon emissions at the same time. This approach aligns closely with India's renewable energy and climate goals. Cities such as Ahmedabad and Hyderabad have already demonstrated the effectiveness of reflective roof coatings.
Another key lesson from Bhopal is the value of data-driven planning. The project relied on satellite observations, urban surface analysis, and modelling tools to identify and evaluate cooling interventions. Similar approaches should become standard practice across Indian cities. Investments in urban climate intelligence may prove just as important as investments in physical infrastructure.
More broadly, the Bhopal study changes the way urban heat is understood. For years, heat adaptation has largely focused on individual protection through fans, coolers, and air conditioners. The smart surfaces approach shifts the focus towards collective solutions that cool the urban environment itself.
As temperatures continue to rise, this shift becomes increasingly important. Cities cannot depend on air conditioning alone to cope with the climate crisis. The financial costs, energy demands, and social inequalities associated with that approach are too great. Creating cooler urban environments through better planning, greener infrastructure, and smarter design offers a more sustainable and equitable path forward.
Bhopal's experiment suggests another possibility: cities designed to remain cooler by default. Through reflective roofs, greener streets, smarter materials and better urban planning, the built environment can become part of the solution rather than part of the problem.
Whether other Indian cities follow Bhopal's lead remains to be seen. But as heatwaves grow longer, hotter and more frequent, the question is no longer whether urban cooling is necessary. The real question is how quickly city governments can scale the kinds of interventions that Bhopal has now demonstrated to be technically feasible, economically attractive and socially transformative. The answer may determine how liveable India's cities remain in a warming world.