The Andaman and Nicobar Islands are home to some of the most isolated and vulnerable tribes in the world, with five groups classified as “particularly vulnerable.”

These include the Jarawas, North Sentinelese, Great Andamanese, Onge, and Shompen. While the Jarawas and North Sentinelese remain largely uncontacted, the Shompen – some 400 people – of the Great Nicobar Islands are also at risk of losing their way of life due to external pressures.

A nomadic tribe, most of them live deep inside the forest where they forage for survival – not much is known about their culture as very few of them have ever had contact with the outside world.

“The loss will be especially huge and traumatic for them,” says Mr Justin, who has been documenting the island since 1985.

“Whatever we call development in the outside world is not of interest to them. They have a traditional life of their own.”

Environmentalists say there are also huge environmental costs of the project.

Spread across 921 sq km (355.6 sq miles), around 80% of the Great Nicobar island is covered with rainforests, which are home to more than 1,800 animals and 800 flora species, many of which are endemic.

The federal environment ministry has said that only 130 sq km or 14% of the total area of the island will be cleared for the project – but that’s still about 964,000 trees. Experts warn the actual number could be much higher.

“The government always claims only a part of the forest will be cleared. But the infrastructure you’re building would lead to more pollution, which in turn would impact the entire habitat,” says Madhav Gadgil, an ecologist.

The environment ministry did not respond to BBC’s request for comment.

But Environment Minister Bhupendra Yadav in August had said that the project “will not disturb or displace” tribespeople and that it had received environmental clearances based on the “rigour of environmental scrutiny and after incorporating consequent safeguards”.

Yet, not everyone is convinced.

Earlier this year, 39 international experts from different fields of social sciences had warned that the development project would be a “death sentence” for the Shompen as it would destroy their habitat.

It’s a fear that haunts Mr Justin too: “The Shompen people do not have the knowledge or the means to survive in an industrial world,” he says.