Urban daytime heat can be reduced by 4ºC even as global warming worsens

As Indian cities endure increasingly intense summers each year, the country’s next battle against extreme heat may not be fought with more heatwave alerts alone, but by redesigning the cities themselves. Why? Because doing so could cut temperatures down by as much as 4°C.A roadmap has been laid out to cool India’s urban landscapes, arguing that roads, rooftops, pavements and shrinking green spaces are turning cities into heat traps, and that better urban planning could help reverse the trend. An aerial view of a cityscape, depicting urbanisation and heat island effect. (Photo: Unsplash) The new report, released by the RMI India Foundation in collaboration with the Lodha Foundation, said that India’s cities are increasingly trapped in the Urban Heat Island (UHI) effect, a phenomenon where concrete, asphalt and buildings absorb and retain heat, making urban areas significantly warmer than their rural surroundings."India is a growing economy and no country has grown without urbanisation," said Aun Abdullah, Programme Director, Sustainable Urbanisation at Lodha Foundation. "When we do that, it eventually leads to no green cover and more concrete. It then manifests itself as the Urban Heat Island effect." The UHI effect can raise temperatures in cities by around 2-10°C above neighbouring rural areas, the report said."If we want that not to happen, then we have to build cities better," said Abdullah. An image shows a dense urban neighbourhood in New Delhi. (Photo: Unsplash) FROM RESPONDING TO HEAT TO PREVENTING ITIndia’s heat policy is undergoing an important shift: from treating heat as a disaster requiring emergency response to addressing it as a long-term urban planning challenge, the report noted.For more than a decade, Heat Action Plans (HAPs) have focused on issuing early warnings, preparing hospitals, ensuring water availability and spreading public awareness to reduce heat-related deaths.While these measures remain essential, they do little to address the built environment that amplifies heat in cities. The root cause of the problem remains. Workers and others rest at the India Gate lawns on a hot summer day, in New Delhi. (Photo: PTI) Instead, the report recommended integrating urban heat mitigation into existing planning systems by promoting reflective roofs and pavements, expanding tree cover and green spaces, and replacing hard, impervious surfaces with more permeable materials that allow water to cool the ground naturally.Together, these measures can reduce the amount of heat cities absorb and retain during the day.HOW DELHI BECAME THE EXAMPLETo demonstrate how cities can identify and tackle heat hotspots, researchers modelled different cooling interventions in Delhi’s Planning Zone-F, covering parts of South Delhi, New Delhi and South-East Delhi. A view of concrete road and footpaths on a hot summer's day. (Photo: Unsplash) The modelling found that built-up areas, asphalt roads and barren land consistently recorded the highest land surface temperatures, making them priority targets for intervention.Residential neighbourhoods offered the greatest potential for reflective roofs and paved surfaces, while institutional campuses and open spaces were better suited for greening measures.In the end, it concluded that combining interventions such as reflective built surfaces, greening barren land and improving surface permeability could lower the zone’s average daytime land surface temperature by up to 4.3°C. A woman is seen resting under a tree in a park in Lodhi Garden, Delhi. (Photo: Unsplash) But, as the report cautioned, this estimated dip in temperature applies only to the Delhi case study and would vary across cities depending on land use and surface characteristics.A BLUEPRINT FOR COOLER CITIESRather than calling for entirely new institutions, the report argued that India already has many of the policies and programmes needed to cool its cities.It instead recommended bringing existing urban development, disaster management and environmental initiatives under a coordinated framework through a proposed National Programme for Urban Heat Mitigation, anchored by the National Disaster Management Authority (NDMA).Such a programme would help mainstream heat mitigation into city planning, financing and infrastructure decisions, allowing urban areas to move beyond reacting to heatwaves and instead reduce the heat they generate in the first place.- EndsPublished On: Aug 5, 2026 18:28 IST