The Supreme Court issued an order in February to remove forest-dwellers in 21 states where nearly 2 million land claims, each potentially representing a household, were rejected under the Forest Rights Act (FRA) of 2006.
The court later stayed its order to give states more time to examine the rejected land claims.
WHY DOES THIS CASE MATTER?
The FRA aimed to improve the lives of impoverished tribes by recognising their right to inhabit and live off forests where their ancestors had settled, and to govern them.
Under the law, at least 150 million people could have their rights recognised to about 40 million hectares of forest land.
But states have been slow to implement the law, and more than half the claims were rejected, often on flimsy grounds, indigenous activists say.
India's 104 million tribal people - also known as Adivasis, or "original inhabitants" - make up less than 10% of the population.
Yet they accounted for 40% of people forced from their homes between 1951 and 1990, often without compensation or resettlement as more land is sought for highways and mines, according to the Centre for Policy Research (CPR) think-tank.
WHAT HAS INTERNATIONAL REACTION BEEN?
Indigenous rights group Survival International said India's eviction order was a "death sentence" for its tribal people that would lead to the "biggest mass eviction in the name of conservation".
Victoria Tauli-Corpuz, the United Nations' special rapporteur on the rights of indigenous people, said the "basic premise of this decision, which treats tribal peoples as possibly illegal residents of the forest, is wrong".
"This is a phenomenon seen around the world," she said in a statement earlier this month.
"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."
WHAT IS THE ARGUMENT AGAINST FRA?
The case challenging the validity of the FRA was brought by a group of conservationists and wildlife organisations who say it leads to fragmentation of forests, threatening biodiversity and wildlife and causing deforestation.
The government's draft National Forest Policy 2018 proposes to tax some produce, give forest officials more power against encroachers, and earmark more land for afforestation, which will boost commercial plantations, according to land rights groups.
If enacted, the new forest policy would make the FRA almost ineffective, thus depriving millions of poor indigenous people of their right to forest land, human rights activists say.
WHAT IS THE GOVT STANCE?
Indigenous activists say the government failed to defend the FRA at the Supreme Court, and only acted after protesters took to the streets following the top court's eviction order.
Government authorities then asked the Supreme Court for more time to verify the claims.
The Tribal Affairs Ministry has said it will defend the constitutional validity of the FRA, and "do everything to safeguard the interests of the tribals".
Land in India is a state matter, and each state has different laws related to its use, acquisition, governance and taxation. There are also federal laws on these matters.
A study of just eight of India's 29 states by CPR showed that there are more than 1,200 laws related to land. Some date back to the colonial era, and many contradict each other, sparking conflicts and lengthy legal battles.
There are more than 700 disputes over land across India, affecting nearly 8 million people, and more than 2.3 million hectares - or 8,880 square miles, roughly the size of Djibouti - according to research organisation Land Conflict Watch. (Reporting by Rina Chandran @rinachandran; Editing by Katy Migiro. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's and LGBT+ rights, human trafficking, property rights, and climate change. Visit http://news.trust.org)