There has been an increasing trend of urban flood disasters in India over the past several years whereby major cities have been severely affected. Most recently, Bengaluru was brought to a standstill due to flooding of the city (2022). In the 2020 floods in Hyderabad, thousands of houses were submerged. Similarly, the 2015 Chennai flood was devastating. To combat such occurrences, cities have mostly relied on traditional approaches of flood management termed ‘Grey Infrastructure’. Grey infrastructure refers to structures such as dams, seawalls, roads, pipes, or water treatment plants.

Issues with this traditional approach to flood management:

• The infrastructure often gets overwhelmed during heavy downpours due to the reduced capacity of installed pipelines, flood storage, drawbacks in the operation of pumping stations, and a general lack of maintenance.
• Extreme precipitation events could lead to frequent run-offs, which could exceed the capacities of current urban drainage systems. Therefore, areas along the rivers or the coastlines and inland areas are vulnerable to increased risks of flooding, rising sea levels, and uncertain precipitation patterns.
• The current global issues, such as increased urbanization, higher run-off volumes, and climate change, have put a strain on the existing systems. The problems have particularly escalated in the face of climate change that impacts rainfall patterns, intensities, and their frequencies.
• It becomes difficult to upgrade the existing grey infrastructure with changing dimensions and changing loads.

Therefore, there is a need for alternative approaches to urban flood management. Many cities around the world are adopting nature-based solutions (NBS) that are socio-ecologically sound to reduce the loss of lives and livelihoods from urban floods. These measures can be exercised at both ends of the system, from individuals in households to local government bodies. They include the following:

• Setting up urban forests, terraces, and slopes, open green spaces, and corridors.
• Other components include urban farming and bioretention areas, natural or constructed inland wetlands, river and floodplain restoration, riparian buffer formation or rejuvenating and installing mangroves and salt marshes, based on space availability and the nature of the ambient topography, city site, and size and its socio-economic profile, need to be incorporated.
• Adopting eco-friendly practices from various states/union territories country-wide, such as:

• • Jammu and Kashmir’s eco-restoration policies to fight against climate change.
  • Emphasis on the importance of open spaces within built-up areas, preservation of watersheds and wetlands, reconnecting the floodplains, and afforestation, as done in Guwahati (Assam).
  • Some notable nature-based solutions to combat urban drainage issues and environmental impacts are Bhopal’s Green and Blue Master Plan, Delhi’s Master Plan 2041, Chennai’s ‘Water as Leverage’ initiative, and Pune’s urban agricultural plan.

India’s urban population is expected to reach 814 million by 2050, with the addition of four new megacities by 2030. Therefore, there is an urgent need to recognize and advocate the adoption of NBS at the national level to mitigate urban flooding and include them as crucial components of city Master Plans and urban renewal schemes in India.