For the residents of Tansi Nagar in Velachery, Chennai, the arrival of the rains signals not relief, but a looming threat of flooding that damages their homes, property, and hard-earned possessions. These families are forced to vacate their houses, needing boats, tractors, and other makeshift transport to relocate. This grim reality affects more than 10,000 families living in the Velachery area, including neighbourhoods such as Annai Indira Nagar, Anna Nagar, Balamurugan Nagar, Venus Colony, Sarathi Nagar, Bhuvaneshwari Nagar, VGP Selva Nagar, Seshathripuram, EB Colony, and Balakrishnan Nagar. 

Rainwater from this entire locality drains through the canal adjoining the Perungudi Railway Station Road, entering a six-vent watercourse, then flowing into the Pallikaranai Marshland, before emptying into the Buckingham Canal and eventually reaching the Bay of Bengal. Currently, this natural drainage system is severely blocked by encroachments and indiscriminate construction, including residential buildings, apartments, religious centres, car sheds, a hospital, and a few compound walls. Over the years, private and politically backed groups have illegally occupied the six-vent canal and nearby areas, with support from certain officials.

In 2018, nearly 500 metres of the canal were filled with sand up to 10 feet deep, and buildings were constructed over it. Following a report in Dinamalar, the Madras High Court took suo motu cognisance of the situation and ordered the removal of the encroachments. Although the authorities complied with the High Court’s order by demolishing the illegal structures, they failed to clear the debris and sand. This continued to obstruct the flow of rainwater and ultimately defeated the purpose of the Court’s directive.

No respite from waterlogging

Because of this negligence by authorities, these neighbourhoods were under five feet of water for a week during the 2023 floods — with no power, no drinking water, and no essentials.

In March 2024, the Tansi Nagar Welfare Association met with the Chennai District Collector, the Commissioner of Greater Chennai Corporation (GCC), and other government officials and submitted a petition with 2,000 signatures, demanding the removal of recent encroachments that had cropped up after 2018. Even this did not yield any action from the authorities.

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Meanwhile, the GCC took control of the six-vent watercourse from Southern Railways, under whose jurisdiction it previously fell. Instead of restoring the canal, GCC used the debris left behind in 2018 to construct embankments and ended up creating a pond.

The six-vent culvert was originally completed in October 2021 by Southern Railways to channel rainwater into the marshland and provide a link to the stormwater drain network. According to the GCC, the pond is expected to hold a substantial volume of rainwater, thereby helping to prevent flooding in the surrounding areas. 

It is a well-known fact that the Pallikaranai Marshland plays a vital role in Chennai’s ecosystem by absorbing vast quantities of rainwater and acting like a natural sponge. This crucial function helps to reduce flooding and waterlogging in neighbouring areas during the monsoon.

The marsh’s unique water-retention capacity and ecological balance have evolved over centuries and cannot be replicated through artificially created ponds or tanks. Protecting and restoring this natural wetland is essential for sustainable flood management, groundwater recharge, and biodiversity conservation in the region.

Residents take legal recourse

Since multiple petitions given to civic authorities and government functionaries were ignored, residents have approached the courts and filed a new case under the banner of the Tansi Nagar Welfare Association in December 2024.

In March 2025, the High Court directed the Tahsildar of Velachery to survey all encroachments, sand heaps, and blockages in the six-vent canal and take steps for the removal of encroachment within 12 weeks, i.e., on or before June 12^th, 2025. The tahsildar was also instructed to submit a report to the court and the association within five days of the inspection. Although the Revenue Department inspected and issued notices in June, no further action, such as demolition and removal of debris, has taken place.

Meanwhile, the Corporation has begun “beautification works” by laying new roads, dumping sand, and planting trees right on the drainage path. All petitions and the order of the Madras High Court to stop the work have been ignored. While new urban amenities and infrastructure may enhance convenience and aesthetics, they do not justify or override the urgent need to protect people’s lives and property during every monsoon.

To draw the attention of the public and administration, members of the association hoisted black flags outside their homes on October 12^th to register their protest against the lethargic and indifferent approach of the civic authorities in ensuring residents’ safety. On the same day, the members also wore black badges, assembled and raised slogans against the authorities.

What the community wants

As a last resort, the Tansi Nagar Association has now filed another writ petition demanding:

• Putting an immediate stop to the plan for developing a park, garden and creating a pond.  
• Removal of the encroachments and immediate restoration of the six-vent watercourse.
• Providing another six-vent culvert for faster draining of rainwater into the marsh, and widening the canal to 30 feet from the recovered land. 
• Increase the height of the six-vent culvert to enable desilting and removal of debris using machines; currently, this is being done manually due to the low level of the culvert.

Also read:

• Civic activists oppose government’s plan to shrink Bengaluru’s vital drain buffers
• Saving Kavesar Lake: Citizens campaign against beautification plans for Thane wetland
• Staying afloat: From Davanagere to Copenhagen, how cities are successfully battling urban floods