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Nature-based Solutions are emerging as a promising approach to rejuvenate waterbodies, which face degradation of the water quality and ecological integrity
This article is part of the essay series: The World Water Week 2025
According to the NITI Aayog report, 60 crore people in India encounter extreme to high water stress—a crisis worsened by the rise in population and the consequent increase in domestic and industrial effluents. Only a fraction of the wastewater gets treated before it is discharged into water bodies. The contamination of water has led to existential threats to biodiversity and human communities. It's difficult to set up and maintain expensive water treatment plants with specialised equipment. In such a scenario, nature-based solutions (NbS) offer a compelling alternative: they treat water safely and biologically, recycling it within the community. They are easy to maintain and create beautiful public spaces while utilising existing infrastructure, thereby reducing costs.
It's difficult to set up and maintain expensive water treatment plants with specialised equipment. In such a scenario, nature-based solutions (NbS) offer a compelling alternative: they treat water safely and biologically
In the first-ever census of waterbodies conducted in India by the Ministry of Jal Shakti, India is home to 2,424,540 water bodies, with 2,355,055 in rural areas and 69,485 water bodies in urban areas. These vast networks of waterbodies—including lakes, ponds, rivers, and wetlands—have historically functioned as critical ecological and socio-economic assets. These systems provide multiple ecosystem services, including potable water supply, groundwater recharge, flood risk attenuation, and the maintenance of biodiversity. However, accelerated urban expansion, unregulated industrial effluent discharge, spatial encroachment, and the compounding effects of climate variability have led to a marked decline in their ecological integrity. In metropolitan regions such as Bengaluru, Chennai, and Hyderabad, numerous lakes that once supported vibrant aquatic ecosystems have been transformed into highly degraded, pollution-laden basins or have been systematically reclaimed for commercial and residential development.
Stormwater run-off, contamination with sewage and nutrient input from various sources have led to eutrophication, causing the overgrowth of algae. These blooms are further exacerbated by urban pollution and are often accompanied by invasive species such as water hyacinth, which outcompete the native flora. Both these factors, the algal blooms and invasion by water hyacinth, lead to a very high chemical/biological oxygen demand (COD/BOD), creating a “dead zone”. There have been incidents of mass deaths of aquatic animals in various waterbodies across the country. The hypoxic conditions also lead to emission of methane, which is a potent greenhouse, with a greenhouse effect 20-30 times greater than that of carbon dioxide. As per reports, CH4 production is greatly enhanced by algal blooms. The problem of eutrophication, thus, contributes to climate change as well. The stagnant water also acts as a breeding ground for mosquitoes and pathogens, posing a threat to the nearby communities. The pathogens can also enter the groundwater through the lakes, contaminating it as well.
The International Union for Conservation of Nature (IUCN) defines NbS as “actions to protect, conserve, restore, sustainably use and manage natural or modified terrestrial, freshwater, coastal and marine ecosystems, which address social, economic and environmental challenges effectively and adaptively, while simultaneously providing human well-being, ecosystem services, resilience, and biodiversity benefits.”
These include phytoremediation, where pollutant-tolerant plant species absorb, metabolise, or immobilise contaminants; floating wetlands, which are buoyant platforms for vegetation that intercept and treat surface water; constructed reed beds, designed to mimic marsh ecosystems for filtering wastewater; and riparian buffer zones, vegetated margins that stabilise banks, reduce runoff, and enhance habitat connectivity.
These interventions replicate and enhance natural biogeochemical cycles. For example, floating islands with plants like Vetiveria zizanioides (vetiver grass), Canna indica (canna lily), etc., can effectively remove nitrates, phosphates, and heavy metals from polluted urban lakes. Apart from taking up the nutrients themselves, the plant roots provide extensive surface area for microbes to grow. These biofilms formed on the roots of plants and are also responsible for nutrient uptake and degradation of various pollutants. The process of bioremediation through the floating islands helps in reducing the emission of methane from water bodies and provides a carbon sequestration system to the waterway, which is important towards combating climate change. They also serve as important artificial ecosystems, providing habitats for plankton, birds, and several other organisms. Waterbodies are also treated with beneficial bacteria that help to break down organic components as well as metabolise excess nutrients such as nitrogen and phosphorus. Such systems operate without synthetic chemicals, relying instead on microbial activity, plant uptake, and sediment interactions to purify water—making them both low-impact and resilient.
NBS offer long-term value with lower maintenance costs and higher adaptability to climate variability as artificial wetlands can stand fluctuating water depths.
Economically, NBS are cost-effective and a sustainable investment. Unlike conventional grey infrastructure—such as concrete flood barriers or drainage systems—NBS offer long-term value with lower maintenance costs and higher adaptability to climate variability as artificial wetlands can stand fluctuating water depths.
Several Indian cities have successfully implemented NbSto restore urban waterbodies. In Hyderabad, the restoration of Neknampur Lake stands as a model for community-led NBS. Launched in 2018, the project employed floating wetlands and bio-remediation techniques to combat pollution and invasive species like water hyacinth. Floating wetlands planted with vetiver grass were deployed, which reduced biochemical oxygen demand (BOD) by 90 percent. A number of lakes in Bangalore, such as Kyalasanahalli Lake, Kaikondrahalli Lake, Jakkur Lake, and Puttenahalli Lake, have been restored to life through eco-restoration techniques and community-driven efforts. Annapurna Lake in Indore, which was covered with water hyacinth and had witnessed mass fish deaths in the past, was transformed through floating wetlands, added microbial cultures and a solar-powered aerator. Nationally, initiatives like the Atal Mission for Rejuvenation and Urban Transformation (AMRUT) have been launched, which promote a circular economy of water through the development of City Water Balance Plan (CWBP) for each city, focusing on the recycle/reuse of treated sewage, rejuvenation of water bodies and water conservation by integrating NBS into urban planning.
Despite their potential, the implementation of NBS faces obstacles. Funding constraints remain a major barrier, hindering large-scale projects.
Despite their potential, the implementation of NBS faces obstacles. Funding constraints remain a major barrier, hindering large-scale projects. Policy fragmentation—between central schemes like AMRUT and state-level initiatives—leads to inconsistent application. Community resistance stemming from a lack of awareness makes it difficult to keep lakes in a healthy state for longer periods. Only with concerted efforts from all stakeholders, India's waterbodies be revived, ensuring water-secure, livable cities for generations to come.
Priyanshu Kumath is the CEO of Clean-Water (Sustainable Water Technologies Private Limited).
Sonam Mandani is the Chief Technology Officer at Clean-Water.
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Priyanshu Kumath is the CEO of Clean-Water (Sustainable Water Technologies Private Limited). ...
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