India’s Supreme Court is set to decide the fate of almost two million forest-dwelling families facing what activists say would be the world’s largest mass eviction in the name of conservation.

At a hearing on Wednesday, the apex court must decide whether to uphold its eviction notice towards all households living in protected forest areas whose claims to the territory under the Forest Rights Act (FRA) have been denied.

Those affected include many members of India’s “adivasi” or indigenous community, rights groups say, whose claims to their ancestral land have been rejected due to a lack of paperwork or flaws in the application system.

Wildlife conservation groups say the FRA has been used by encroachers to snatch land in previously unoccupied forests, much-needed habitats for endangered species including pangolins, sloth bears, the one-horned rhinoceros and India’s national animal - the tiger.

But tribal leaders and the Indian government say the FRA provides much-needed protections to some 104 million adivasis who have historically lost out the most as their resource-rich lands were plundered to fuel the country’s economic boom in the second half of the 20th century.

Nicholas Barla, a tribal leader of the Oraon people in Odisha state, said that of around 150 families in his village, 70 were facing eviction.

He described how the villagers maintained a traditional way of life, praying in special places of worship in the forest, surviving off the produce of different fruit trees and bushes for months at a time and maintaining a “peaceful coexistence” with wildlife that goes back thousands of years.

“We are feeling anger and uncertainty,” he told The Independent. “We have lived in a peaceful manner for all of history together with the animals here, but today suddenly the Supreme Court and the forest department want to evict us. I do not understand.

“The indigenous communities lived here before the formation of the country. So it is actually the government who has encroached on our territory. I ask the judge - please, do not send us to some other place where we do not know, and we do not want to go.”

It is in part the tribal people’s isolation from modern society deep in forests, the thing they are trying to preserve, which has led them to be caught up in the threatened evictions.

Even those with some of the most seemingly clear-cut claims to ancestral land have faced a hostile bureaucratic system requiring dozens of supporting documents, often without success.

Guruvaiah, a leader of the protected Chenchu tribe that has occupied lands in what is now the Amrabad Tiger Reserve for thousands of years, said his village never heard back on whether their claim under the FRA was successful, and that they were now worried the Supreme Court would kick them out.

“The forest department want to kick us out of the forest in the name of protecting animals,” he said. “But we believe the forest is our mother. We say the tiger is our brother. We protect the forest, we won't let anyone come to disturb the forest in any way.”

The petitioners in the Supreme Court case argue that human habitation of any kind in the forests leads to the fragmentation of wildlife habitats, and are calling for reform of the FRA.

While they have not recommended changing the regulation, the judges did rule in February that state governments must act when land claimants had failed at the final point of appeal, with records showing 1.89 million people were continuing to live in the forest despite being told they had no right to do so.

That ruling was suspended for nearly five months after the government requested more time for the application system to be investigated, and it is understood that some state governments will submit requests on Wednesday for up to another 18 months to get their records in order.

The confusion surrounding their status has inevitably led many tribals to question the authorities’ motives. Mr Barla said he suspected “there may be minerals in my village” and that the government would hand the land over to corporations for mining once the indigenous people were evicted.

Guruvaiah said the problem was that the tribal people, some of India’s most impoverished and under-resourced, had to rely on others to advocate on their behalf.

“We are just forest lovers. We are not politicians, we do not have money, and we are very few. We will always have to depend on someone,” he said.

VS Roy David, national convener of the National Adivasi Alliance, blamed the looming evictions on “the tiger lobby”.

“We are hoping the Supreme Court will postpone again,” he said. “These people are just creating problems saying that if communities live there there will be conflict between the humans and the animals. This is not true.

“The adivasis are not encroachers, they are the virgin settlers and it is their homeland. Their way of life revolves around protecting the animals and the forest. They maintain the ecological balance, not disturb it.”

The tribal leaders did accept, however, that some genuine encroachment of protected forests by outsiders was taking place, though they argued that this paled compared to the logging and mining operations that the authorities either permitted or turned a blind eye to.

Praveen Bhargav, trustee and co-founder of Wildlife First, one of the groups petitioning for the Supreme Court to reform the FRA, said the situation with regards to the loss of forests in India was “alarming and all pervasive”.

He said studies showed that almost 6 per cent of the country’s forest coverage vanished in the thirty years to 2005, and that a government report in 2015 found another 2.5 per cent was encroached by illegal human settlements.

Bhargav said evidence showed that wildlife populations recovered when reserves were “strictly protected”. “Harmonious co-existence between people and large wildlife in the Indian context is a myth,” he said.

“While it is imperative that we redress injustices done to impoverished forest dwellers, it is vital that we do not perpetuate injustice to wildlife and forests, which have neither a voice nor a vote,” he told The Independent. “We must not forget that wildlife colonised this planet much before the first human set foot [here].”

If it upholds its ruling, the Supreme Court would be doing so in the face of international condemnation.

Victoria Tauli-Corpuz, the UN special rapporteur on the rights of indigenous people, said in a statement earlier this month that the "basic premise of this decision, which treats tribal peoples as possibly illegal residents of the forest, is wrong".

"Indigenous peoples and local communities are treated as squatters when in fact the land is theirs, and they have protected and stewarded their holdings for generations and play an important role for conservation,” she said.

The indigenous rights group Survival International, which has campaigned on the issue, said Supreme Court risked passing a "death sentence" for India’s tribal people that would lead to the "biggest mass eviction in the name of conservation”.