The police defused a tense stand off between two groups of people over the partial demolition of a bund linking the islet of Edayar with the Thiruvallam mainland on Monday.

A construction firm contracted by the State government to build a seawall at Poonthura had constructed the barrier for ferrying construction material to the coastline.

Subsequently, the residents of Poonthura and the islets of Edayar and Panathura found the mud dam an easy route to access Thiruvallam.

However, the barrier prevented the outflow from the Parvathy Puthanar from reaching the sea. The stagnant waters caused much pollution in the locality, chiefly the religiously important bathing ghats of the Thiruvallam Parasurama temple.

On Sunday night unidentified miscreants partially demolished a section of the bund, triggering a potentially violent situation in the neighbourhood, the police said. The next day, a section of people from Poonthura and Edayar attempted to repair the damaged portion by dumping jute sacks filled with sand. A tense stand off developed when some people on the mainland attempted to resist the move to repair the bund.

Senior police officials arrived at the spot and talked separately to leaders of both the groups. Later, they agreed to settle the matter amicably in the presence of local representatives and officials.

The Karamana river which coursed through the city merged with the Killi river at Pallathukadavu (upstream of Thiruvallam) and flowed around the Edayar island, on its way to the Poonthura estuary. Both the rivers carried raw sewage discharged from the city. The polluted Parvathy Puthanar canal joined the river at Munnattumukku, near Poonthura. The flow of water on the western side of the island was often blocked due to silting at Munnattumukku and accretion of sea sand at Kunnumanal.

During high tide, seawater from the estuary surged up to Thiruvallam through the eastern side of Edayar. When the tide ebbed, the polluted water from the Parvathy Puthanar rushed in upstream. Local residents said the temporary bund had worsened the water pollution in the area.