The Chennai Rivers Restoration Trust (CRRT) has initiated a comprehensive plan to restore 70 km of the polluted Kosasthalaiyar river, focusing on the stretch downstream of Red Hills to the estuary. The 136-km-long river, which originates from Chittoor in Andhra Pradesh, remains largely clean until Red Hills, with pollution concentrated in North Chennai.

CRRT is coordinating with the Water Resources Department (WRD), Metrowater, and Greater Chennai Corporation (GCC) for the project. WRD has proposed a Rs 81 lakh plan to establish boundary stores to prevent encroachments. A consultant, Voyants, identified 13 solid waste dumping points, which the GCC has been tasked with clearing. A centralised solid waste processing facility is also planned at Kondakarai to handle waste from nearby panchayats.

Metrowater will plug five sewage outfalls at a cost of Rs 1.75 crore and implement an underground sewerage system in Idayanchavadi, Sadayankuppam, and Kadapakkam by September 2026. The plan includes identifying and relocating encroachments along the riverbank. In Manali’s Sadayankuppam area alone, over 1,000 encroachments have halved the river’s carrying capacity from 1.1 lakh cusecs to 60,000, contributing to severe flooding in 2023. Proposals will be sent to the Tamil Nadu Urban Habitat Development Board to relocate affected residents.

The restoration work is expected to commence within a month, pending budget allocations for each department involved. The WRD emphasied that systematic planning and coordinated execution are key to restoring the river's ecological balance and flood-carrying capacity.