New Delhi: The Tamil Nadu government on Monday urged the Centre to drop the proposal to set up the India-based Neutrino Observatory (INO) at Theni district in the state. The Chief Minister of Tamil Nadu, M K Stalin, wrote to Prime Minister Narendra Modi, recalling he had sent a memorandum in June last year, media reports said. 


Stalin had requested the Government of India to drop the proposal of setting up the particle physics observatory at Pottipuram village in Theni district. 


Stalin wrote to the Prime Minister that “this request was made in the larger interest of conservation of the rich wildlife and biodiversity of the region, as the project would cause irreversible damage to the fragile and sensitive ecosystem”. 


According to reports, the site being proposed for the Neutrino project falls within the Mathikettan, which is the Periyar Tiger Corridor as mapped by the National Tiger Conservation Authority (NCTA). The chief minister said that the corridor has the critical function of maintaining the genetic flow, which will be destroyed due to project activities. 


What Are Neutrinos?


A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass. Neutrinos are one of the most abundant particles in the universe and are incredibly difficult to detect because they have very little interaction with matter. 


These particles are abundantly found in nature. Every second, the Sun, the stars and the atmosphere produce millions of neutrinos. Also, most of these neutrinos pass through our body. Since neutrinos interact very less with anything that comes in their path, they can even pass through the Earth. 


Neutrinos are harmless as they interact weakly, and can also be made artificially. These subatomic particles are created in radioactive decay and in nuclear reactors.


What Is The India-Based Neutrino Observatory (INO)?


The India-based Neutrino Observatory (INO) Project is a multi-institutional effort aimed at building a world-class underground laboratory with a rock cover of approximately 1200 metres for nuclear physics research in India. The INO Project also aims to conduct non-accelerator based high energy research, according to the project’s official website. In particle physics, an accelerator propels charged particles, such as protons or electrons, at high speeds, close to the speed of light. The INO project is a national mega science and engineering project.


More than 50 scientists from about 15 Institutes and Universities in India have come together to form the National Neutrino Collaboration group (NNCG), which has the task of detailing various aspects related to INO activity.


The INO Project is jointly funded by the Department of Atomic Energy (DAE) and the Department of Science and Technology (DST). 


What Does The INO Project Involve?


The INO Project involves the construction of an underground laboratory and associated surface facilities at Pottipuram in Bodi West hills of Theni District of Tamil Nadu, according to the project’s official website. A large cavern with a size of 132 m X 26 m X 20 m will be a part of the underground laboratory. The site is close to the elephant corridor between the Western Ghats and the Eastern Ghats.


The project also involves the construction of an Iron Calorimeter (ICAL) detector for studying neutrinos. The aim of the calorimeter is to achieve a statistically significant number of neutrino interactions in a reasonable time frame with good energy and angular resolution.


Also, the calorimeter will consist of 50,000 tons of magnetised iron plates arranged in stacks with gaps in between, where Resistive Plate Chambers (RPCs) would be inserted as active detectors.


The INO Project also involves setting up of an Inter Institutional Centre for High Energy Physics (IICHEP) at Madurai. This is meant for the operation and maintenance of the underground laboratory, human resource development and detector research and development, along with its applications.


What Does The INO Project Aim To Achieve?


The proposed underground neutrino observatory has been named as the Pottipuram Research Centre (PtRC) of the INO. The main goal of the Project is to set up an observatory deep underground under a hill near Pottipuram village in Theni, which will observe the sky through neutrinos.


The INO Project aims to study neutrinos, which come in three flavours. One of the flavours is associated with electrons, and the other flavours are associated with the heavier cousins of electrons: muon and the tau. The main focus of the project is to explore the Earth's matter effect by observing the energy and other parameters of atmospheric neutrinos. The underground facility is expected to develop into a full-fledged underground science laboratory for studies in physics, biology, geology, hydrology, astrophysics, cosmology and other fields. The INO Project will help answer several questions about neutrinos. 


The first phase of the project aims to study atmospheric neutrinos produced by interactions of cosmic rays in the Earth's atmosphere. Just as a telescope observes the sky through visible light, the Iron Calorimeter detector will observe the sky through neutrinos. 


Many long-term options are associated with the project. For instance, researchers can use the INO Project for solar and supernova studies in the future. 


Why Has A Hill Been Chosen As The Site?


Several particles are produced in the atmosphere. In order to avoid the difficulty of identifying and separating signals produced by the neutrinos from those produced by other particles, the detector will be kept inside a mountain. The neutrinos will easily pass through the mountain, and reach the detector, while other particles will be filtered out by the mountain rock.


Since neutrinos can easily pass through anything, they will reach the detector while the other particles will be filtered out by the rock in the mountain. Muons and other particles will lose their energy in their way and will eventually stop.


According to a fact sheet on the project’s official website, the unusual feature of the laboratory is that it has to be about 1,000 metres or more underground. A cleaner neutrino signal could be obtained in the laboratory because the rock material of the Earth will absorb the background particles and radiation. 


According to the project’s website, an underground neutrino facility in India offers the unique possibility of locating a neutrino detector near the Earth’s equator. Solar neutrinos could pass through the core of the Earth in their passage from the Sun to the detector  at night.


How Will The INO Project Benefit The Country?


The INO Project will prove to be a game changer because it will help enhance the country’s scientific manpower. The detectors used in the INO Project will be useful in fields such as Medical Imaging, and will merge various disciplines, according to the official website.


When Was The INO Project Conceived?


A document was presented to the Department of Atomic Energy in 2002. The document laid out an ambitious goal of establishing an India-based Neutrino observatory, and since then, many developments have taken place in neutrino physics. A Neutrino Collaboration Group (NCG) was established, which involved scientists from different research institutes and universities.


On August 30, 2002, the directors of the participating institutes signed a memorandum of understanding (MoU) to enable smooth functioning of the NCG, and to create an underground neutrino laboratory.


In 2005, the project was conceived, and by 2009, the proposed site was identified. In 2015, the Union Government approved a budget of Rs 1,583 for the INO project, based on cost assessments done in 2012.


Why Is The INO Project Being Resisted?


The chief minister of Tamil Nadu wrote to Modi that the tunnel and cavern will be at a depth of 1,000 metres from the top of the mountain, and that at this depth, mountain rock would be under “tremendous pressure and the vertical stress is expected to be greater than 270 kg per sq.m”. The chief minister explained to Modi that this will create problems like rock bust and roof collapse, according to a PTI report.


The fact that the project site falls within the Bodi Hills West Reserve Forest, which lies in the Southern Western Ghats, is also a matter of concern. This is because the Western Ghats are considered a global diversity hotspot harbouring numerous endemic species of flora and fauna, Stalin said.


“This area also links ecologically to the eastern habitats where Srivilliputhur Meghamalai Tiger Reserve is located and hosts tigers from the region and assists in genetic dispersal across the Western Ghats and their South-Eastern projections through the Cumbam Valley. Along with tigers, its co-predators, several other species of mammals including the ungulates, reptiles and amphibians move around the slopes of these hills,” Stalin wrote. 


Also, the area forms a significant watershed and water catchment for Sambal and Kottakudi rivers. Stalin said that small streams on the west side of Bodi Hills join the Kottakudi river which joins the Periyar river before draining into the Vaigai dam, and that this watershed is the lifeline of local communities. This is because the watershed supports their livelihood and provides water for drinking and agricultural needs for five districts of Tamil Nadu.


In September last year, a state ministerial delegation met Union Minister for Industries and Commerce, Piyush Goyal, and requested him to drop the INO project considering the serious repercussions that can be caused by it.


Stalin requested the Prime Minister to intervene in the matter, and to advise the authorities to drop the INO Project in Tamil Nadu.