The environmental and social costs of the Vizhinjam port rail tunnel will be higher than anticipated

Proposed railway tunnel from Vizhinjam.

The state government’s decision to construct an over ₹1,500 crore railway tunnel to the Vizhinjam International Seaport through a densely populated region, despite the availability of alternative land layouts, has raised eyebrows among many, with experts and the public questioning its environmental and social costs against the backdrop of the state government’s stated commitment to sustainable development.

The proposed tunnel between Balaramapuram and Vizhinjam to provide a rail link to Vizhinjam International Seaport has raised serious concerns about the environment and country stability in the region. Set to become the state’s second major tunnel project and the country’s third longest rail tunnel, the project has been questioned about its feasibility under the Vizhinjam-Balaramapuram road by experts who termed it potentially unviable given the region’s fragile geology, soil types and high population density.

Dr. V. Nandakumar, former head of the Natural Hazards Research Group and former director (in-charge) of the National Center for Earth Science Studies, said that no comprehensive study involving competent national institutions on the geological formations along the proposed 10.7 km alignment, variations in soil types or the flow of ground water from east to west had been done before the project began.

Based on more than three decades of field experience, Mr. Nandakumar said most sections of the proposed alignment are likely to lead through geologically weak terrain. Beneath the upper layer of laterite, the subsurface is expected to consist of decomposed lithomargic clay interbedded with hard rock in some places. Other sections consist of inconsistent red soil underlain by layers of clay and sand. According to him, such formations are unsuitable for a tunnel transporting several tons of container trains.

The proposed route also passes through some of the most densely populated areas of Thiruvananthapuram district, where a large portion of the population depends on open wells for drinking water. He warned that the impermeable concrete structure of the tunnel, laid at a depth of around 30 meters, could act as an underground barrier and disrupt the natural movement of groundwater. This could eventually cause wells to dry up in an area already facing water shortages.

He also drew attention to the risk of vibrations generated by heavy container trains passing through tunnels bored into weak soil. Such vibrations could damage existing structures, from large buildings to smaller houses, causing cracks and, in extreme cases, structural collapse. Landslides and damage to buildings could pose long-term risks along the entire stretch, he warned.

He also expressed his opinion on whether the authorities have sufficiently investigated alternative routes through lower lying areas, including the edges of the Pallichal-Mudavoorpara paddy fields, which is 10 m lower in elevation than the proposed tunnel route, which is 30 m below the road surface and almost parallel in height to the port and the Nager Tricovandrum rail link. According to him, such a route could prevent potential threats to densely populated areas and minimize risks to existing structures, groundwater resources, environmental stability and local livelihoods.

It could also reduce construction and maintenance costs. The surface-level alignment would also offer more room for future doubling and widening of the line, which would be difficult to achieve with the proposed tunnel, he said. The project in its current form could destabilize the region and disrupt the livelihoods of millions of people living along the Balaramapuram-Vizhinjam corridor. The land above the tunnel, including the buffer zone, could remain locked up subject to restrictions on development, planning permission and other uses. This may even affect property ownership and transfer rights. Disposal of excavated rock and soil created during tunneling could represent another major environmental challenge.

He called on the government to reconsider the tunnel proposal and instead opt for an overland rail alignment after proving its economic viability. Senior government officials said they chose the route as the shortest route among the existing rail lines to the port, although a relatively lower-cost land route through the region’s rice paddies is available.

Published – 12 Nov 2026 07:00 IST