The EIA pertains to a revised alignment that now includes tunnels through ecologically sensitive hilly terrain, a design change meant to reduce environmental damage and address earlier objections over extensive hill cutting.

NHAI will use the report to seek fresh environmental clearance from the Union ministry of environment, forest and climate change.

Before that, however, the authority must obtain consent from the state pollution control board, a process that is expected to include a public hearing next month.

"The submission of EIA report is a crucial milestone. We are now preparing for the statutory public hearing and will soon approach pollution control board. Once that is completed, we can move ahead with application for environmental clearance from Centre," an NHAI official said.

The proposed six-lane corridor spans roughly 65 km from Vizhinjam to Navaikulam and falls under the Centre's Bharatmala Pariyojana, designated as national highway NH 866.

It is expected to ease congestion on city roads and strengthen access to the Vizhinjam International Seaport.

The project had been stuck after its reclassification as a national highway invalidated earlier state-level environmental clearances, creating a bottleneck that stalled land acquisition, compensation and tendering.

Action council convener S Chandramohan Nair cautioned that the process must remain fair to affected communities. "While we welcome any forward movement, the process must be transparent. The concerns of landowners and environmental safeguards cannot be overlooked in the rush to secure clearances," he said.

The project is planned under a hybrid public-private partnership model and has received approval from the Public Private Partnership Appraisal Committee.

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