The Government of India has approved a project to build the India-based Neutrino Observatory (INO) at Pottipuram in the Theni District of Tamil Nadu. Briefly, the project aims to set up a 51000 ton Iron Calorimeter (ICAL) detector to observe naturally occurring atmospheric neutrinos in a cavern at the end of an approximately 2 km long tunnel in a mountain. There is no other neutrino detector anywhere in India at present. ICAL at INO would be the first of its type.

The INO project does not disturb the ecosystem around the site and does not release any radiation, as it does not have any radioactive substance. It measures cosmic rays.

What is a Neutrino?
The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was originally thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles.

A neutrino interacts only via the weak subatomic force and gravity. The weak force has a very short range, gravity is extremely weak on the subatomic scale, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.