Delhi's Concrete Sprawl Turns Up the Heat
Vanishing green cover and shrinking water bodies have made Delhi's built-up core measurably hotter than its outskirts, a new municipal report finds, complicating the city's response to record heatwaves
Synopsis
Satellite data has indicated that the ground surface temperature in parts of Delhi was above 60 degree Celsius in 2026 summer while the periphery of the city was comparatively green. The ground surface temperature, observed with satellite data, had a significant difference between the densely built core and the greener periphery areas of Delhi during the summer of 2026. The city's green cover had reduced by almost half in the previous decade, according to an analysis by Centre for Science and Environment. The article reviews the drivers that have led to the increasing urban heat island phenomenon in Delhi, and the initiatives undertaken by the administration from cool roofs to targeting hot spots via satellite mapping.
A City Warming Unevenly
India Meteorological Department (IMD) issued heatwave alerts for the Delhi region as maximum temperatures were projected to hit 44 degrees Celsius for a third day, in late April 2026.
Ground level readings, in fact, paint an even clearer picture: The Delhi Heat Action Plan 2026 has satellite thermal data that shows the surface temperature breached over 60 degree Celsius in Narela and more than 59 degree Celsius in the area of Najafgarh, well above the air temperature.
In June 2026, a study done by the Centre for Science and Environment revealed that more than three-fourths of the city of Delhi has become persistently heat-stressed. The report showed that in 2014, Delhi had more than 25 per cent of its urban area covered by green, which has reduced to about 14 per cent by 2024, while its water-body footprint has decreased proportionately.
The Core-Periphery Divide
This cooling was found to be as high as 3.97°C during the night in Delhi's dense urban core compared to the peri-urban areas, where residents can enjoy natural cooling during the night due to the lower heat stress. These are directly attributed to the construction patterns of dense low-rise buildings, narrow lanes with limited cross-ventilation and almost complete absence of local water bodies.
The impact is felt more by the unauthorised colonies in Delhi that have an estimated 40 to 45 lakh residents (figures vary across government estimates) and are the subject of a regularisation initiative planned for 2026, which has been criticised for not linking heat-mitigation measures – including roof treatment or shade planning – to legalisation.
The Administration's Response
The government of Delhi has implemented a ‘Cool Roof Policy' for reflective coatings on the public buildings, as well as 'misting stations' at bus stops and an increase in emergency health facilities (over 339 health centres on alert and over thirty hospitals with dedicated health centres for heatwaves). Chief Minister Rekha Gupta has forecasted an electricity grid stress of over 9,000 megawatts during the peak summer season, which is significantly higher than last year's peak.
The potential to compensate for the loss of green cover and water bodies resulting from a structural change over a 10-year period is unclear at this point. As opposed to emergency season measures, reforestation, restoration of wetlands and building codes which account for climate change are proposed to reverse the heat trajectory in Delhi, researchers argue.