Environment

Every monsoon, South Chennai goes underwater. The only sponge that soaks up all that rain is the Pallikaranai Marsh, yet around it, 8,619 hectares of land face severe flood risks. Despite this, the State has offered to protect only a fraction of that land.  On October 9th, the Tamil Nadu State Wetlands Authority (TNSWA) told the Madras High Court  that the marsh's interim Zone of Influence (ZoI) is just 36 survey numbers, covering 128.19 hectares. The next hearing of the case is on November 11th.  Scattered "protection"  These plots lie in bits and pieces across seven villages, from Pallikaranai to Perumbakkam.…

In Chengalpattu district, the main water channels of the Kovalam-Nemmeli coastal wetland, which drains a catchment of more than 270 square kilometres, have currently been blocked. Barriers that obstruct water flow have been built across Chennai's Buckingham Canal at three places: Thiruvidanthai-Vadanemmeli, near the Nemmeli-Thiruporur bridge, and Saluvankuppam. Earlier, we explored how the Mamallan Reservoir causes serious damage to the wetland’s ecology and how fishing livelihoods are affected. Field investigations by the Wetland Conservation Network have recorded the blockages preventing tidal exchange in the Buckingham Canal.           According to officials, these barriers were put up to enable construction of the Mamallan…

Long before Mumbai’s relentless summer even began this year, the city was already simmering. In March, Mumbai was hit by a severe heatwave, with the temperature reaching a five-year high of 40° Celsius. As rapid urbanisation and a flurry of infrastructure projects replace dense tree cover with steel and mortar, heatwaves seem to have gone from being rare occurrences to an annual threat.   The Mumbai Metro Rail Corporation Limited (MMRCL) cut a whopping 3,093 trees in Aarey Colony to make way for Mumbai’s Aqua Line ( Metro 3). For environmentalist Stalin Dayanand, this is not just a temporary problem.…

During the Open City biodiversity datajam held in December 2025, our group examined the ecological trends around Bengaluru’s lakes. Our analysis suggests a majority of waterbirds are declining across the city's lakes. Earlier, we addressed crucial questions on how migrant and resident waterbirds are surviving across 14 of Bengaluru’s lakes, how the shape of the lakes influence microhabitats, and how a scoring system can be used to record the decline in lake quality and bird populations. The last of our four-part series turns its attention to an individual site. As part of this study of waterbirds in 14 city lakes,…

While bird detection trends over the years clearly point to the decline of Bengaluru’s shoreline and vegetated-edge habitats, numbers alone tell only part of the story. In Part 3 of this four-part series on the state of the city's waterbirds, we have used a scoring system to understand how stressed the lakes and the microhabitats within the lake are, based on the bird diversity they support. We explore how lake shape, permanent inundation and shifts in citizen-led management might explain why some lakes may thrive as wetlands while others collapse.  For instance, at Kasavanahalli, the Pied Kingfisher and the Coot…

As work on the Mamallan Reservoir project is picking up pace, environmentalists and locals dread the devastation it is unleashing. The project not only threatens the fragile Kovalam-Nemmeli coastal wetland and the habitats it supports, but also poses flood risks to communities living nearby.  In an earlier article, we showed how field studies by the Suzhal Arivom team documented the damage this project will cause to the local ecology. Based on that same report, Part 2 looks at how the project impacts the daily lives and livelihoods of people in the Kovalam-Nemmeli area. The project can trigger the erasure of…

A few months ago, there was widespread uproar over attempts to convert a small part of the Pallikaranai Marshland in South Chennai into multi-storey apartments. Yet today, the equally vital Nemmeli coastal wetland in Chengalpattu district faces silent destruction. Richer in biodiversity and livelihood support than Pallikaranai, the Nemmeli wetland, also known as the “Great Salt Lake,” is being converted into a freshwater reservoir by the Tamil Nadu government, purportedly to boost drinking water supply to Chennai. But the project spells disaster. Phase one of the Mamallan Reservoir project involves acquiring more than 5,000 acres of land, removing topsoil, and…

More than 1,000 trees to be cut. Close to 100 bird species and 400 plant species endangered. All this for a project that covers just about two kilometres and costs a whopping ₹1,140 crore. Residents and activists in Bengaluru have vehemently opposed the Karnataka government's Hebbal Short Tunnel project, launching a petition to halt construction immediately. Environmental activists and experts warn that the project threatens Bengaluru's cascading lake system and increases flooding risks. There is growing public concern that the tunnel will cut through one of North Bengaluru’s last major green-blue landscapes and cause lasting environmental damage. The petition, started…

Since Bengaluru’s lakes were formed by damming water flowing down valleys, they are typically wedge-shaped, with a gentle slope and a deep basin towards the embankment. This promotes the growth of diverse vegetation and animals, each adapted to a particular water depth. The result is a natural zonation – reedbeds and shoreline vegetation at the edges, floating and submerged vegetation in the middle, and open water at the deepest end. During the Open City biodiversity datajam held in December 2025, our group examined the ecological trends around Bengaluru’s lakes. In an earlier article, we examined how migrant and resident waterbirds…

Over the past few years, maths teacher Usha found her classroom sweltering during her usual 12.50–1.50 pm period, on the second floor of Perunthalaivar Kamarajar Government Girls Higher Secondary School. “It was so difficult to take class during the peak hours,” she says. But this year, she mentions that it feels slightly bearable, and attributes this to the shade of the trees, the wind blowing through the building, and the latest addition — solar-reflective paint on the roof. Data from a state government and UNEP Cooling pilot project at the Ambattur school shows that reflective coating brought the classroom’s internal…