Indigenous leaders on the frontline of the climate crisis are calling on the Science Museum to cancel its sponsorship deal with a company they say is responsible for widespread destruction in their homelands. Leaders from communities in Australia, India and Indonesia warned that the museum’s new agreement with Adani Green Energy, whose parent company Adani Group is a major operator of coal mines and coal-fired power stations, is legitimising its “destructive coal expansion activities”. In a letter to the museum, they state: “Indigenous communities in all these countries are experiencing land-grabs, repression, the destruction of sacred lands, pollution of air, land and water and, of course, the worsening impacts of climate change exacerbated by burning coal.” The appeal follows criticism of the museum over its deals with fossil fuel giants – and companies associated with them – in the midst of a climate crisis. In recent months it has faced resignations and protests over its relationship with Adani Green Energy and Shell. Last month the Guardian revealed how two scientists had refused to allow their work to be featured by the museum, with dozens more coming out in support of a boycott a few days later. In Tuesday’s letter Adrian Burragubba, spokesperson for the Wangan and Jagalingou Family Council in Australia; Phillip Kujur, from Adivasi Activist Forum for Indigenous Rights, Jharkhand, India; Siti Maimunah, from Jatam, Indonesia, and Joseph Zane Sikulu, from the Pacific Climate Warriors, accuse the director of the museum, Sir Ian Blatchford, of dismissing indigenous concerns during a recent appearance on the BBC. Responding to comments from an indigenous spokesman, Blatchford appeared to question the truth of some of the accusations being put forward and said “some campaigners exaggerate very significantly those issues”. The letter says that the move to “dismiss the concerns of Indigenous peoples” is “completely unacceptable for any publicly funded institution, and particularly concerning coming from a museum of science”. It adds: “When Indigenous peoples approach the museum with deeply held concerns that their rights are being violated by one of its partners, they must be respected, listened to and acted upon, not dismissed as exaggerated and untrue.” In response Blatchford said it was not his “intention to comment on the detailed working practices of Adani Mining nor to dismiss the concerns of anyone”. He added: “The point I was seeking to make … was that it would be for Adani Mining to respond to allegations about its activities in Australia and that a proper discussion of such allegations should involve other relevant voices, in this case the people impacted by mining activities, the mining company and the Australian government.” The Adani Group did not respond to requests for comment about the accusations in the letter. Previously it has insisted it is “very supportive” of traditional communities and cultures. It has also said its coal mining projects in India have improved the country’s energy security and boosted employment, education and healthcare. Mary Archer, chair of the museum, defended its relationships with Adani Green Energy which she said was one part of the Adani Group, “which includes five other businesses with interests spanning ports, airports and coal mining”. “Each of the businesses is an independent, publicly traded entity with its own board of directors,” she added in a letter. “This clear distinction is important, specifically because of Adani Green Energy’s potential to have a very positive impact, both in supporting millions of people in India who have currently no access to electricity and in expediting India’s transition away from coal.” Archer also defended the museum’s wider sponsorship deals with fossil fuel companies. “Given the enormous expertise and wealth tied up in major energy companies, they need to play a much bigger role in urgent change to prevent a climate catastrophe … We believe the right approach is to engage, debate and challenge companies, governments and individuals to do more to make the global economy less carbon intensive.”