When I arrive at Rangapoli, in the Indian state of Orissa, the villagers tell me how they used to grow millet, beans and peas. They harvested leaves, pineapple, jackfruit, mango, banana, chillies, ginger, turmeric, bamboo and roots from the forest. Fresh water was plentiful. But according to the villagers, the opening, in 2008, of an aluminium refinery in neighbouring Lanjigarh by Vedanta Aluminium Limited (VAL), a subsidiary of a British-based mining group, has brought misery, disease and impoverishment.

The refinery has created two red mud ponds the size of several football pitches near Rengopali into which bauxite ore is washed, along with chemicals, causing toxic fumes and polluted dust. Lutni Majhi, a woman living in the village, tells me, "Now, not only is it hot during the day, it is hot at night, as the refinery is functioning at night. Before, we had forest and trees around us, it was much cooler. We've never had this much heat, flies and mosquitoes." The water sources are exposed to dangerous contamination.

Global health and Safety regulations stipulate that a refinery should be at least 10km from villages; this one is situated in the midst of these hill dwellers' natural habitat. New diseases affecting people's lungs and eyes are already widespread. In a report prepared for India's Ministry of Environment and Forests, site inspectors were told that 13 people in the area have died from TB in the past two years and 200-250 cattle and goats have perished. I speak to a man who is dying from a respiratory illness resembling TB. His wife is distraught: she will be left alone to fend for herself and their children.

Vedanta has received unconditional support from the state of Orissa to expand the refinery, and to start an open-pit bauxite mine in the Niyamgiri hills. Now it has been given the green light from the Supreme Court of India it is waiting only on final clearance from the Ministry of Environments and Forests.

There are approximately 80 million tribal people in India, among them 15,000 Kondh, an indigenous tribe who have lived in Orissa for generations. The Dongria ("hill-dwelling") Kondh live in the lush forests of Niyamgiri mountain, a pristine ecosystem of great significance to conservationists. The Kondh rely on the forest and streams to graze livestock, and gather food and medicines and vital drinking water. They consider the mountain to be a living god, and claim that their spiritual, cultural and economic wellbeing are embedded deep within it. The Dongria Kondh are considered an endangered Primitive Tribal Group and are recognised as "a people requiring particular protection". They used to own 400 acres of land. Now they have only 60 acres. Every day is a struggle to survive.

In 2002, Vedanta approached the communities surrounding Lanjigarh, informing them that they were going to build a factory. Vedanta had promised employment for everyone, assuring the Kondh that only one village would be displaced. In 2003, Vedanta forced the community of Kinari to vacate their village and coerced farmers into selling their land at far below its market value. Hundreds of people have now been displaced. The few who had titles to their land were promised 100,000 rupees (£1,450) per acre; those without titles were promised a one-off settlement of 50,000 rupees to give up all their rights. Those giving up their homes were promised 1,000 rupees (£14). It is believed that Vedanta now owns more than 3,000 acres of land, including forest.

Under Indian law, forest-dwelling communities have the right to land and other resources, but the government of Orissa failed to inform the Kondh of their rights, and Vedanta did not warn them of the potentially devastating impact of its project. According to a UK report: "Vedanta failed to engage the Dongria Kondh in adequate and timely consultations about the construction of the mine… Vedanta did not respect the rights and freedoms of the Dongria Kondh consistent with India's commitments under various international human rights instruments, including the UN international covenant on civil and political rights… the convention on biological diversity and the UN declaration on the rights of indigenous people." Vedanta refutes these allegations.

At Bandhaguda, a village less than 200m from the refinery, I am told a particularly disturbing story. When Vedanta began to cut the forest to build the refinery, 400 men, women and children protested in front of the construction site. The police arrested all the men, keeping them in jail for seven days. When they were released they were told they had become outcasts and needed to go to Puri, to redeem themselves at the Lord Jagannath's temple. The state police were used alongside Vedanta staff to forcibly take the men to far-off Puri. While they were there, the wall of the refinery was built. The Kondh's ancestral graveyard was destroyed and the area illegally enclosed in the Vedanta refinery compound.

On the second day of my visit, , organised by ActionAid, we make our way to another of the Dongria Kondh villages. Tamaksila is a place of quiet mud huts with thatched roofs, holding mahua tree hay. The only sounds are bird calls, the mooing of the indigenous cows and the flurry of poultry scattered by our vehicle. Our hosts take us further down the path that passes through the village. Suddenly, in front of us stands a large gathering of more than 100 members of the Dongria Kondh. Many of them have come to meet us and share their concerns about the imminent threat to their sacred mountain and their way of life posed by the planned Vedanta bauxite mine.

I am moved by the beauty of the place, and as soon as we come up the hill the villagers announce our arrival with drum beats and a traditional welcoming ceremony. Two young men with hand-made drums start singing a slow, rhythmic song about Niyamgiri. A group of beautiful young girls join in singing with the boys, and dance arm-in-arm. Their music is peaceful and rhythmic, the lyrics are poignant – they eulogise the mountain and list the gifts it has given them. The song ends with the line, "We will not leave Niyamgiri".

A group of smiling women surround me and put their arms around my waist, leading me to my assigned seat. They give me a bouquet of scented flowers and welcome everyone by putting the traditional "tika" on our foreheads, made with the paste of turmeric and rice. The women and girls are wearing their traditional colourful clothes, beaded jewellery, hairpins, ear- and nose rings, and head necklaces. In contrast, the men wear plain dhotis. Many have long hair tied into a knot in the nape of their necks. Some are carrying axes on their shoulders and in their hands. One can already see the influence of "development" in some of the young men wearing shirts and T-shirts.

We all sit in a circle: the men, women and children sit on the ground, but as soon as I ask questions they stand up and begin to tell me, with great urgency, their concerns and fears that Vedanta is going to destroy their mountain and their livelihoods. Kuleska Patru, one of the leaders, says to me, "Without our mountain, our god, there is no life for us; we will resist the forced expulsion till death. Just as a fish cannot survive outside of water, the Kondh cannot survive without Niyamgiri."

The message the Kondh ask me to take to the Indian government, the chief minister of Orissa, Vedanta and their shareholders is loud and clear: "No amount of financial reward or relocation packages can compensate for the loss of our livelihood and our sacred land"; "Please tell Vedanta that the Kondh do not want the mine to be built."

Their hope is that the government of India and the chief minister of Orissa, Naveen Patnaik, will respect their livelihood, their culture and their human rights and prevent Vedanta from causing the irreversible destruction of Niyamgiri mountain.

Having campaigned about these issues for nearly three decades, I speak from experience when I say that the Kondh's battle to save their livelihoods illustrates the struggle for survival that tribal and indigenous peoples are facing throughout the world.

Vedanta's modus operandi is not an isolated case. Today, exploitation of indigenous peoples is no longer carried out by colonial adventurers but by businessmen, often representing mining, oil and gas or logging companies, whose policies are implemented in the name of progress. India, desiring to join the developed world, is pursuing policies that use the same senseless tactics as the colonial powers of the past century.

According to the UN, companies have a responsibility to respect human rights wherever they do business. It is deplorable that local people should have to implore and appeal to the better nature of shareholders and company executives to protect their human rights and homes. Companies who violate this fundamental right need to be held accountable, and plans for an Environmental Court of Justice are under way.

In the 21st century, we need to redefine the meaning of "development". It must be sustainable. Any project must take into account the needs and aspirations of the local communities and should benefit all sectors of society. As Our Common Future (the report published by the UN's Brundtland Commission) states, development must "meet the needs of the present without compromising the ability of future generations to meet their own needs". Measures of development need to be more holistic – instead of focusing on GDP, we need to take Human Development Indicators (poverty, health, mortality, education) into account.

There has been some success in our campaign to hold Vedanta to account. In February, the Joseph Rowntree Charitable Trust and the Church of England demonstrated their commitment to human rights by withdrawing investment from Vedanta. Edinburgh-based investment management company Martin Currie has already sold its £2.3m stake on ethical grounds. In 2007 the Norway pension fund withdrew its investment of $15.6m, based on the findings of its ethics committee, which stated: "Allegations levelled at Vedanta regarding environmental damage and complicity in human rights violations, including abuse and forced eviction of tribal people, are well founded."

It is my hope that the Indian government, and particularly the government of Orissa, will do everything in its power to prevent Vedanta from endangering the survival of the Kondh. It is not too late to force Vedanta to adhere to ethical codes of practice that respect human and environmental rights. This may be our last chance to help the Kondh to prevent their way of life disappearing altogether.

At Vedanta's AGM last year, I spoke to Sitaram Kulisika, who was representing the Kondh people at the meeting. "Once they start mining, the mountain will be bulldozed and the rivers will dry up and our livelihood will be lost," he said. "We don't know how to adapt and survive and our way of living is not available in the cities. We will be extinct." ■

To find out more, go to amnesty.org. You can follow Bianca Jagger on Twitter (username BJHRF) or Facebook (Bianca Jagger Kondh Campaign), where you can sign the letter to the chief minister of Orissa.