NHAI Justifies Use of Mamallapuram Pond for ECR Ramp, Cites Safety and Mitigation Measures

The National Highways Authority of India (NHAI) has defended its decision to use part of a Mamallapuram pond for constructing an exit ramp as part of the four-laning of the East Coast Road (ECR) between Mamallapuram and Puducherry. In a submission to the National Green Tribunal (NGT), the agency said the move was essential for road safety.

Responding to a petition that accused the NHAI of encroaching on a waterbody without valid grounds, project director M.S. Chaitanya clarified that only 3,460 sq.m, less than 20% of the 15,000 sq m Solaipoigai tank, was used, mostly along shallow edges. The ramp, he said, is vital to ensure a safe exit from a proposed underpass near the town’s heritage elephant sculpture, addressing what could otherwise be a high-risk traffic junction.

The ECR expansion was aligned in 2018, with contracts awarded in March 2020. Construction began in May 2023. The first objections surfaced in August 2024, with the NGT petition filed in January 2025.

Citing a report by LN Malviya Infra Projects, NHAI stated that about 10,800 cubic metres of earthwork were undertaken using non-polluting materials. The embankment, it said, would not impact the quality of the pond’s mostly static water.

To compensate for the loss, the agency excavated nearby waterbodies in Pooncherry, Perumaleri, Karanai, and Kuzhipandalam, adding over 45,000 cubic metres of water storage. The move aligns with the Centre’s ‘Amrit Sarovar’ waterbody rejuvenation program.

NHAI also submitted that it had secured a no-objection certificate from Tamil Nadu’s water resources department. Alternate alignments were dismissed due to the proximity of a major Buckingham Canal bridge just 1 km away, which made realignment unsafe and geometrically unviable.

The NGT is scheduled to hear the case again in June.