A study by the Center for Study of Science, Technology and Policy (CSTEP) titled Urban Greenprints: Leveraging Nature-based Solutions (NbS) to Address Urban Climate Risks has revealed that while Chennai is making steady progress through its climate action plans and existing green initiatives, it can take additional steps to address the challenges of climate extremes such as heatwaves and flash floods during monsoon.
The research indicated that in selected wards in Chennai, implementing green spaces, urban farms, permeable pavements, and restored wetlands can significantly improve resilience to urban flooding, with co-benefits such as mitigation of heat stress and pollution reduction, while making the city more liveable.
Many of these ideas are simple and cost-effective. For example, in the studied wards in North Chennai, even the modest use of green rooftops, such as turning bare concrete surfaces into low-cost, low-maintenance gardens, could boost local green cover by over 70%. This will result in a major cooling effect in areas that are often the hottest, most crowded, and least green parts of the city. Besides bringing temperatures down, rooftop gardens can help with rainwater absorption and even supply produce for households.
Streets can also play a big role in absorbing water and reducing heat. The report highlights that switching to permeable surfaces in flood-prone areas can allow rainwater to seep into the soil, helping recharge groundwater and reducing waterlogging.
Chennai’s wetlands are another key part of the solution. Neighbourhood lakes and river catchments can serve as natural sponges, absorbing excess water during storms and filtering pollutants. Preserving and expanding these ecosystems can help protect neighbourhoods from flooding while supporting birds, fish, and other wildlife that are part of Chennai’s natural heritage.
As per the report, multiple on-ground projects are already demonstrating that the proposed solutions are effective. For instance, the Chennai Urban Farming Initiative has introduced rooftop and mobile gardens in schools, homes, and homeless shelters. These not only help cool buildings and grow food but also create learning opportunities and jobs, especially for women and young people. In a city where land is limited, using rooftops wisely is a smart and inclusive move.
These changes require investment. The report estimates that around INR 2,203 crore would be needed to put key nature-based solutions into action across selected wards in the city. But it also finds that the economic benefits, like reduced damage from floods, could amount to over INR 500 crore in savings each year. In other words, Chennai could recover the costs in just over 4 years.
What makes this approach more appealing is that it is flexible. Projects can start small, like a community wetland park or a few green rooftops, and scale up over time. It is not about turning the whole city upside down overnight. It is about creating solutions that suit local needs and working with people to bring them to life.
Lakshmi Menon, Senior Analyst in the Adaptation and Risk Analysis group at CSTEP, highlights, ‘In cities like Chennai and Mangaluru, even modest ward-level investments in green infrastructure can yield substantial long-term savings and ecological benefits. As climate risks intensify, integrating nature-based solutions into urban planning is not just desirable—it is essential for building resilient, adaptive, and sustainable cities.’
Nature is not just a victim of climate change; it can be part of the cure. By giving space to trees, water, soil, and people, Chennai has a real chance to become cooler, greener, and more resilient, not just for today, but for future generations.