Nearly two decades after it was proposed, the India-based Neutrino Observatory (INO) project — the most expensive basic science experiment proposed in the country at an estimated cost of Rs 1,500 crore — is yet to take off. The project had received environmental clearance in March 2018.

After overcoming a series of litigations, the INO project seemed to have overcome its hurdles in December 2020 when the Union government notified an area of zero to one kilometre around the boundary of the Mathikettan Shola National Park in Kerala as an eco-sensitive zone (ESZ), effectively placing the INO project site at Pottipuram panchayat in Tamil Nadu’s Theni district outside the ESZ. The national park is located near the Tamil Nadu-Kerala border.

But the project has now met with another bottleneck. During a meeting on 17 February 2021, the Tamil Nadu forest department reportedly informed the Department of Atomic Energy, the funding agency, that the project site falls in the Mathikettan-Periyar tiger corridor. The Tata Institute of Fundamental Research, the project proponent and one among the consortium of 21 institutes involved in the project, was then required to apply for wildlife clearance, which is yet to be examined by the State Board for Wild Life.

Speaking to LCW, Chief Wildlife Warden Shekhar Kumar Niraj confirmed that the project site falls in the tiger corridor. “This brings the state and national boards for wildlife into the picture. Based on their recommendations and the existing laws and policies, the environment ministry will decide on the future course of action.”

Meanwhile, INO Project Director Gobinda Majumder, in a press release, said that the project would not affect the tiger corridor as the tunnel would be constructed several metres underground. “The surface facilities are purely restricted to the 26.82 hectares of revenue land, and they lie completely outside the adjoining reserve forest. Of the 4.62 hectares of underground construction, it is clarified that the tunnel entrance (portal) begins in the revenue land and the horizontal tunnel gets several metres deep before it enters the forest land,” he explained. 

D. Indumathi of the Institute of Mathematical Sciences, who is also a member of the INO Scientific Management Board, told LCW that “not even an inch of the tiger corridor would be occupied” as the portal to enter the tunnel would start well outside the corridor on government land. 

Meanwhile, Tamil Nadu Chief Minister M K Stalin, who has always opposed the project, submitted a memorandum to Prime Minister Narendra Modi on 17 June 2021, listing a number of demands, including the scrapping of the project. Earlier in 2019, the Marumalarchi Dravida Munnetra Kazhagam (MDMK), an alliance partner of the ruling Dravida Munnetra Kazhagam, had launched a campaign against the project. Stalin, who was then the Leader of Opposition, had flagged off a protest rally of the MDMK.

The residents of Pottipuram panchayat have expressed fear that they would be alienated from the pastoral lands and Ambarappar hill, which they consider their deity. They have also raised concerns about the project utilising 3.5 lakh litres of water per day from the Mullaperiyar Dam and fear "radiation leaks" from neutrinos. Responding to the grievances, Dr. Indumathi had said that the rights of the community outside the fenced land would not be taken away. “The water required for the project accounts for just 0.00002 per cent of the annual flow of the Mullaperiyar river, which is equivalent to the demand of 150 families,” she further told LCW.

On 17 February 2022, the state government filed an affidavit in the Supreme Court stating that it would not permit the construction of the INO project in the state as it would cause irreparable damage to the environment in the Western Ghats. The Supreme Court has been hearing an appeal against the National Green Tribunal's decision to uphold the environmental clearance granted to the project.

Responding to the affidavit, petitioner and environmental activist G. Sundarrajan told LCW that the Supreme Court should pass 'suitable orders' based on the affidavit. Despite the state government's opposition to the project, the National Tiger Conservation Authority had issued a no-objection certificate to the project in March 2021. According to Sundarrajan, the NOC has become invalid after the affidavit.  

In March 2022, Chief Minister M K Stalin appealed for the second time to Prime Minister Narendra Modi to reconsider and shelve the project, citing significant environmental and community concerns.

The INO project continues to face opposition from Tamil Nadu’s state government and local communities. The project’s location in the Western Ghats, a UNESCO World Heritage site and one of India’s most critical biodiversity hotspots, has raised concerns about deforestation, groundwater depletion, and the displacement of local communities, particularly tribal populations who rely on the region’s resources.

Environmentalists and activists argue that the ecological costs of tunnelling and building in such a fragile region could have lasting consequences. CM Stalin’s renewed request reflects the growing pressure from both activists and local residents, who argue that the scientific gains do not justify the potential environmental damage.