By Aniket Sawargaonkar, M.Sc., Disaster Management, TISS, India

India is increasingly grappling with extreme heat conditions, driven by rapid urbanisation and climate change. Cities like Delhi, Ahmedabad, Nagpur, and Hyderabad regularly record summer temperatures above 45°C. The Urban Heat Island (UHI) effect—where dense urban cores trap more heat than surrounding rural areas—exacerbates this crisis, making cities several degrees hotter and turning heatwaves into public health emergencies.

• Green and Blue Infrastructure (GBI) offers one of the most effective and sustainable strategies to combat this urban overheating. These nature-based solutions—such as urban forests, wetlands, green walls, and restored water bodies—cool cities through shade and evapotranspiration. A global meta-analysis of over 100 cities found that GBI can lower local temperatures by 2–5°C, with larger and denser features producing the most significant reductions.
• Botanical gardensand large urban parks were found to be ~5.0°C cooler than surrounding areas.
• Urban wetlandsprovided cooling effects of ~4.7–4.9°C, particularly strong in hot, dry regions.
• Street tree canopiesand forested patches reduced nearby air temperatures by ~3.8°C on average.
• Adding just 5% more tree coverin a neighbourhood can reduce temperatures by 1°C.

These cooling impacts are not only environmental solutions but also life-saving interventions. For every 1°C rise in temperature, studies show a several-per-cent increase in heat-related mortality risk. Conversely, each degree of cooling can reduce the burden on healthcare systems and prevent heat-related illnesses such as dehydration, heatstroke, and respiratory stress.

In addition to public health, GBI contributes directly to urban resilience by reducing electricity consumption from air conditioning. Shade from trees alone can cut household cooling energy use by 20–30%, and cities like New York have recorded $27.8 million in annual energy savings due to tree-based cooling.

Cities like Ahmedabad have pioneered Heat Action Plans, but there is immense potential to scale up GBI integration across Indian cities, especially in informal settlements, low-income neighbourhoods, and heat-vulnerable zones. Wetlands in semi-arid cities, shaded transit corridors, and greened rooftops in dense housing blocks could serve as urban “heat buffers”.

By investing in GBI, Indian cities can reduce heat stress, improve air quality, save lives, and build long-term resilience against the intensifying threats of climate change. Extreme heat may be inevitable, but its deadliest impacts are not.

References:

1. Sahani, J., Kumar, P., & Debele, S. E. (2023). Efficacy assessment of green-blue nature-based solutions against environmental heat mitigation. Environment International, 179, 108187. https://doi.org/10.1016/j.envint.2023.108187
2. Marando, F., Heris, M. P., Zulian, G., Udías, A., Mentaschi, L., Chrysoulakis, N., & Maes, J. (2022). Urban heat island mitigation by green infrastructure in European functional urban areas. Sustainable Cities and Society, 77, 103564. https://doi.org/10.1016/j.scs.2021.103564
3. Marquez-Torres, A., Kumar, S., Aznarez, C., & Jenerette, G. D. (2025). Assessing the cooling potential of green and blue infrastructure from twelve U.S. cities with contrasting climate conditions. Urban Forestry & Urban Greening, 104, 128660. https://doi.org/10.1016/j.ufug.2024.128660
4. Budzik, G., Sylla, M., & Kowalczyk, T. (2025). Understanding Urban Cooling of Blue–Green Infrastructure: A Review of Spatial Data and Sustainable Planning Optimization Methods for Mitigating Urban Heat Islands. Sustainability, 17(1), 142. https://doi.org/10.3390/su17010142

Disclaimer: The views expressed in this piece are those of the author/s and do not necessarily reflect the views or policies of AIDMI.