Delhi’s Heat Inequality: Greener Neighborhoods Stay Cooler

Research published April 13, 2026, indicates that expanding tree cover in Delhi, India, can reduce experienced temperatures in neighborhoods by approximately 1°C. The study finds that a modest increase of 8% in green cover can achieve this cooling effect, which nearly doubles the warming impact caused by a comparable expansion of built-up concrete surfaces.

The findings, produced by the policy organization Artha Global’s Center for Rapid Insights in collaboration with data.org’s Capacity Accelerator Network, highlight a significant divide in how heat affects the city’s residents. While greener neighborhoods remain cooler, poorer areas characterized by dense concrete construction face higher temperatures and limited access to cooling resources.

The Impact of Heat Inequality

The study reveals that the physical layout of the city and the wealth of its residents determine the severity of heat exposure. Densely built-up spaces in lower-income areas retain heat for longer periods, exacerbating the risks faced by vulnerable communities.

This environmental disparity is linked to several adverse health and socio-economic outcomes. According to the research, rising heat in these concrete-heavy areas is associated with sleep disruption, illness, loss of work and mental stress.

The vulnerability is particularly acute for the approximately 2 million residents of Delhi who live in slums or informal settlement colonies. These homes are often ill-equipped to protect inhabitants from extreme temperatures.

Study Methodology and Data

To reach these conclusions, researchers integrated high-resolution climate and remote-sensing data with a survey of 2,368 households across all 70 of Delhi’s assembly constituencies. This approach allowed the team to layer citizen experiences over objective micro-climate and built-form data.

The analysis utilized the Global Built-Up Surface dataset, provided by the Global Human Settlement Layer (GHSL), at a 100-metre resolution. Each pixel in this dataset captures the square metres of constructed surface, enabling the identification of neighborhoods with dense, concretized forms and limited ventilation.

The research concludes that heat exposure and health outcomes cannot be understood through temperature averages alone, but emerge from the interaction between urban form, socio-economic conditions, and the adaptation choices available to households.

The Urban Heat Island Effect

Delhi has been ranked as the second most heat-stressed city in the world. The city experiences a pronounced urban heat island effect, where densely concentrated roads and buildings absorb and store solar radiation, while local heat is further generated by motor vehicles, industrial activities, air conditioning, and electricity generation.

The impact is most severe during nighttime. Data from a May heatwave indicated that night-time temperatures in built-up areas were 20°C hotter than surrounding agricultural and forest lands. Lower nighttime temperatures are considered critical for the human body to recover from daytime heat exposure, particularly for residents who lack access to air conditioning.

Proposed Resilience Strategies

Researchers and policy experts are calling for a shift from emergency heatwave plans toward long-term urban infrastructure fixes. The Artha Global study urges the implementation of neighborhood-level heat plans and the classification of tree cover as essential urban infrastructure to protect vulnerable populations.

The report identifies three primary priorities for strengthening heat resilience in Delhi and similar cities:

• Citizen-centred micro-planning to address granular differences in how neighborhoods cope with heat.
• Heat-responsive urban design to reduce the reliance on concrete and increase ventilation.
• Energy systems that are aligned with the rising needs for cooling.

By treating urban forestry as a strategic tool, the study suggests that cities can mitigate the warming effects of concrete expansion and reduce the existing inequality in heat exposure.