India's particle physicists have lost their battle to build a neutrino laboratory — one of the country's biggest physics projects — under the Nilgiri hills at Singara in the state of Tamil Nadu. The government has upheld conservationists' view that its construction would endanger wildlife in the Nilgiri Biosphere Reserve (NBR), an important tiger and elephant habitat.

A new site means a further delay of one year to a project that has already lost four years. ,

The 6.8-billion rupee (US$150 million) India-based Neutrino Observatory (INO) has been mired in environmental controversy since 2006, but physicists were hoping it would be resolved in their favour (see Nature 461, 459; 2009). However, on 20 November India's minister of environment and forests, Jairam Ramesh, informed the scientists that they should not proceed at Singara.

Ramesh wrote that he was acting on a "large number of reports" received against the proposed site and the "very weighty reasons" put forward by Rajesh Gopal, head of forestry in his ministry. Ramesh has suggested the project consider instead a site near Suruliyar, also in Tamil Nadu, that does not pose Singara-type problems.

"Everybody in the INO project is disappointed," says project spokesman Naba Mondal, a physicist at the Tata Institute of Fundamental Research in Mumbai. Project scientists had already considered and rejected the potential site at Suruliyar because there were less available data on the characteristics of the rock that would need to be blasted out to create a cavern to host the neutrino detector. "Preparing a new site means a further delay of one year to a project that has already lost four years due to environmental activism," he says.

Conservationists are pleased, however. "We are indeed relieved," says Tarsh Thekaekara, coordinator of the NBR Alliance, the group that spearheaded the campaign against building the neutrino observatory at Singara. The proposed Suruliyar site is also close to the Periyar tiger reserve, although not in a wildlife corridor as the Singara site is.

Thekaekara says that environmentalists near Suruliyar may decide to challenge the new proposal. "We only represent organizations in Nilgiri," he says. "It may happen that some of the members also active in [Suruliyar] will protest if there is a serious threat to nature." Mondal says that work at the new site will start only after all government clearances are in place.