GANDHINAGAR, 11th May 2026: A new study by Indian Institute of Technology Gandhinagar (IITGN) researchers found that while urban greening remains essential to reduce heat stress, cities need smarter and more climate-responsive planning to ensure that tree cover delivers maximum cooling benefits.
The study analysed 138 Indian cities between 2003 and 2020 across tropical savanna, semi-arid steppe and humid subtropical climates. The researchers found that the cooling benefits of vegetation can vary significantly depending on humidity, canopy density, urban compactness and airflow conditions.
The findings also carry strong equity implications. Researchers noted that the communities most exposed to dangerous heat often live or work in dense and poorly ventilated neighbourhoods with limited access to cooling infrastructure. Better-designed urban greening could help reduce long-term heat vulnerability for these populations.
The findings were published in Nature Communications (https://doi.org/10.1038/s41467-026-72636-w), a peer-reviewed, open-access journal from Nature Portfolio that publishes high-quality research across the natural sciences, engineering, and related fields. The paper was authored by Angana Borah, Adrija Datta, Ashish S. Kumar, Raviraj Dave and Udit Bhatia from IIT Gandhinagar.
Highlighting the key findings, Corresponding Author of the study Dr. Udit Bhatia, Associate Professor, Department of Civil Engineering, IIT Gandhinagar, said, “Greening is essential for climate adaptation and shade gives people immediate relief. Our results show that one-size-fits-all plantation targets miss part of the problem. Cities need greening strategies that are designed for shade, moisture and ventilation together.”
Lead author Dr. Angana Borah, Research Graduate, IIT Gandhinagar, added, “The question is not whether cities should be green. They should be. The question is what kind of green, where and how much. In dry cities, vegetation can provide strong cooling benefits. In humid and compact neighbourhoods, planners also need to think about airflow and moisture build-up.”
The study highlights that Indian cities need integrated urban cooling strategies where shade trees, parks, roadside plantations, open spaces and ventilation corridors are planned together. In humid and dense neighbourhoods, factors such as species selection, canopy spacing, pruning, irrigation and street geometry could all influence how effectively greenery reduces heat stress.
HEAT INDEX
The research team reconstructed ‘Heat Index’, a measure that combines temperature and humidity and better reflects how heat is experienced by the human body, instead of relying only on land surface temperature. Using advanced extreme-aware downscaling techniques, the team generated high-resolution one-kilometre Heat Index maps to better identify dangerous urban heat conditions.
The study combined multiple satellite and urban datasets, including vegetation indices, canopy density measures, night-time light data and Local Climate Zone mapping. The researchers then applied explainable artificial intelligence methods to identify which urban features increased or reduced heat stress and where critical thresholds emerged.
By making model outputs interpretable, explainable AI tools like those used in this study are making complex climate-urban interactions easier for planners and policymakers to understand and act on. The approach echoes India’s commitments at the recently concluded India AI Impact Summit 2026 to deploy AI for the Welfare for All, including AI for Social Good.
One of the study’s key findings is that urban greenery does not behave as a single uniform factor. While vegetation cover and canopy structure were linked to lower Heat Index levels once greenness crossed certain thresholds, very high canopy activity in humid and densely built neighbourhoods was sometimes associated with increased Heat Index levels.
The researchers explained that trees cool cities through both shade and evapotranspiration. In dry climates, evapotranspiration can significantly reduce heat because the surrounding air can absorb additional moisture. However, in humid and compact urban areas, excess moisture can remain trapped near the ground, increasing humid heat stress even though shade continues to offer local comfort. The authors cautioned that the study operates at a city-scale resolution and does not yet provide species-specific or street-level prescriptions. Future research will aim to connect these large-scale urban patterns with finer street-level and plant-level observations to support more precise urban planning decisions.
The study’s central message is that trees remain indispensable for climate adaptation, but future-ready urban greening must go beyond increasing green-cover targets alone. Under hotter and more humid climate conditions, cities will need greening strategies that simultaneously provide shade, manage moisture and preserve airflow.
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