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Recently, the National Green Tribunal (NGT) upheld the environmental clearance granted to the India-based Neutrino Observatory (INO), a major research facility proposed in Theni district of Tamil Nadu. While this removes all current legal hurdles in building the facility, there are still other obstacles to be overcome before work can begin on this project, which has been in planning since 2001.

In December 2017, the Cabinet Committee on Security cleared the India-based Neutrino Observatory project, to be built at an investment of Rs 1,500 crore.  It is the latest in a series of neutrino detectors, neutrino factories and experiments being set up worldwide to promote research in particle physics.


A neutrino is a sub atomic particle with no electric charge. They are considered to be the second most abundant particle in the universe, after photons, or light particles. Neutrinos were initially thought to be massless particles but recent experiments suggest that they indeed have a very small mass


India-based Neutrino Observatory

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 approx.1200 m for non-accelerator based high energy and nuclear physics research in India.

The project includes

  1. Construction of an underground laboratory and associated surface facilities at Pottipuram in Bodi West hills of Theni District of Tamil Nadu,
  2. Construction of a Iron Calorimeter (ICAL) detector for studying neutrinos, consisting of 50000 tons of magnetized iron plates arranged in stacks with gaps in between where Resistive Plate Chambers (RPCs) would be inserted as active detectors, the total number of 2m X 2m RPCs being around 29000, and
  3. Setting up of National Centre for High Energy Physics at Madurai, for the operation and maintenance of the underground laboratory, human resource development and detector R&D along with its applications. The underground laboratory, consisting of a large cavern of size 132m X 26m X 20m and several smaller caverns, will be accessed by a 2100 m long and 7.5 m wide tunnel.


The initial goal of INO is to study neutrinos. Neutrinos are fundamental particles belonging to the lepton family. They come in three flavours; one associated with electrons and the others with their heavier


cousins the muon and the Tau. According to standard model of particle physics, they are mass less.


However recent experiments indicate that these charge-neutral fundamental particles have finite but small mass which is unknown. They oscillate between flavours as they propagate. Determination of neutrino masses and mixing parameters is one of the most important open problems in physics today. The ICAL detector is designed to address some of these key open problems in a unique way. Over the years this underground facility is expected to develop into a full-fledged underground science laboratory for other studies in physics, biology, geology, hydrology etc.


What is the aim of India-based Neutrino facility?

The INO promises to be a one-of-its-kind facility to detect and study neutrinos. These are extremely tiny elementary particles that are omnipresent in universe but very difficult to detect because they pass seamlessly through all kinds of matter.

The India-based Neutrino Observatory (INO) is a proposed Pure-Science underground laboratory. Its primary goal is to study the properties and interactions of neutrinos.

INO project is jointly supported by Department of Atomic Energy (DAE) and Department of Science & Technology (DST) with DAE acting as the nodal agency. Tata Institute of Fundamental Research (TIFR), Mumbai is the host institute for INO project.


The World of Neutrinos

Neutrinos are everywhere. They permeate the very space all around us. They can be found throughout our galaxy, in our sun and every second tens of thousands of neutrinos are passing through your body. But there is no need to become alarmed for these tiny particles barely interact with anything. In fact, they can even pass through the entire Earth without being affected.

Neutrinos are fundamental particles that were first formed in the first second of the early universe, before even atoms could form. They are also continually being produced in the nuclear reactions of stars, like our sun, and nuclear reactions here on earth. Much is still unknown about these particle, they have an undetermined mass and travel at near the speed of light.

The Standard Model of Physics

The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions and not including the gravitational force) in the Universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks.

Since then, confirmation of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.


There are three types of neutrinos: electron neutrino, muon neutrino, and tau neutrino. According to the standard model there exist 12 fundamental particles. Each “flavor” of neutrino has a corresponding charged particle from which it gets its name. The Standard Model consists of three generations and each generation has two quarks a neutrino and a charged particle. The particles in the standard model are separated into two types: quarks and leptons. The quarks interact via the strong nuclear force while the leptons interact via the electromagnetic or the weak nuclear force. Neutrinos are nearly massless and have no electric charge. Therefore, unlike the other particles, they only interact via the weak nuclear force. Neutrino actually means “little neutral one.” Since the weak nuclear force only acts at shot ranges, neutrinos can pass through massive objects without interacting with them.


Neutrinos can change from one flavor to another as they travel. This process is called neutrino oscillation


The Sun, and all other stars, produces neutrinos copiously due to nuclear fusion and decay processes within their core. There are many other natural sources of neutrinos including exploding stars (supernovae), relic neutrinos (from the birth of the universe), natural radioactivity, and cosmic ray interactions in the atmosphere of the Earth. Neutrinos are very difficult to detect because of their extreme inertness. They have an extremely low tendency to interact with other objects, and pass seamlessly through any object that comes in their way. The neutrino density of the universe is 330 per cubic centimetre.

Neutrinos carry no electric charge. Predicted in 1931, neutrinos were detected for the first time in 1959, and are now considered to be the second most abundant particle in the universe — after the photon, or light particle. Groups in many countries are carrying out research on neutrinos, believed to hold important clues to some of the basic questions on the universe. Research on neutrinos has led to award of the Nobel Prize in Physics in 2002 and 2015, and before that, in 1988 and 1995.


FAQs regarding India- Based Neutrino Project

Where is the India neutrino observatory being planned?

At Pottipuram village, in Theni district, near the Tamil Nadu-Kerala border.

What does it entail?

It is an underground project and will comprise a complex of caverns. The main cavern, which will house the huge neutrino detector [50-kilo tonne magnetised iron calorimeter], will be 130 m long, 26 m wide, and 30 m high.   Two smaller caverns will be used for setting up experiments for neutrino double detector and dark matter. Approach to this complex will be by a 2-km-long tunnel.

What is a neutrino?

Neutrinos are the smallest particles that form the universe.

Who else has a neutrino facility?

Underground: SNO, Canada, Kamioka in Japan and Gran Sasso, Italy.

Underwater:  Amundsen-Scott South Pole Station, Antarctica.  Antares – under Mediterranean sea off coast of Toulon, France.

Who is in-charge of the project?

The Tata Institute of Fundamental Research is the nodal institution. The observatory is to be built jointly with the Department of Atomic Energy and the Department of Science and Technology.

What’s special about locating the INO in the South?

A project report says most of the neutrino detectors are at latitudes over 35 deg. It is possible to push such a detector down to almost 8 deg latitude in South India, within proximity to the Equator. This permits neutrino astronomy searches covering the whole celestial sky and study of solar neutrinos passing through the Earth’s core.

Why are the locals opposing it?

Locals fear that the excavation and blasts needed to bore the tunnel in the mountains will endanger the biodiversity of the Western Ghats.   Some of the concerns voiced range from radiation, structural damage to the mountain to emission of hazardous chemicals.

What do scientists say?

Scientists have junked all these claims as baseless and unfounded.

What next?

In March, the Tamil Nadu government has formed a committee to seek public opinion on the Observatory. The State government will take a decision based on the panel report. Meanwhile, there is talk of the project being moved to Andhra Pradesh, which is rolling out the red carpet for new projects.


Applications of Neutrino Science

Information on the evolution of Universe: Neutrinos hold the key to several important and fundamental questions on the origin of the Universe and the energy production in stars. As neutrinos can travel long distances and remain uninterrupted over time, they can provide knowledge about the origin of the universe and the early stages of the infant universe, soon after the Big Bang. Composition of universe: If the properties of neutrinos can be studied better, they can be used in astronomy to discover what the universe is made up of. Properties of the sun: The visible light that reaches us from the sun is emitted from the surface of the sun. Solar neutrinos produced in the core of the sun can give us information about the interior of the sun. Neutrino science and INO laboratory can greatly aid the development of detector technology and its varied applications. For example: in the areas of medical imaging.


Concerns associated with INO:

Proximity to Dams: There are 15 dams storing over 3 billion m3 of water within radii of 5 to 70 km from the proposed site. Construction of underground observatory with deep tunnel in close proximity to dams raises concerns over reservoir triggered seismicity, change in hydro-geology and possible floods

Blast-induced earthquakes: A massif made up of hard and brittle charnockyte rock will be blasted during the construction process which may lead to stress related problems like rock bursts. The potential damages to buildings and dams near the site of the project from rock bursts is a serious concern

Aquifer impacts: The impact on the aquifers and underground springs is a major concern. For example: the disruption of the aquifer during the tunnelling at the time of construction of Italy’s Gran Sasso National Laboratories (LNGS) resulted in death of several workers and a massive flood in the plains. Further, the chronic impacts on the groundwater level were more massive and irreversible

Impact on ecology and Wildlife: Environmentalist have raised concerns over the possible impact on ecology and wildlife due to INO’s close proximity to Mathikettan Shola National Park in Kerala’s Western Ghats

Concerns over radioactive emissions: Many have raised concerns about the possibility of nuclear or radioactive emissions. However, the government has said the concern is not true and INO has been involving in mass awareness exercises regarding the same.


INO and the Series of holdups

The project has been mired in all kinds of trouble — litigation, public protests, opposition from NGOs and political parties, besides government apathy. It has had to move locations once, because the nearby Mudhumalai National Park had been declared a tiger reserve during the same time. Environmental clearance granted in 2011 for the second site, too, was put in abeyance by the NGT because the project was within 5 km of the Mathikettan Shola National Park in Idukki, and no application had been moved for the approval from the National Board of Wildlife.

Fresh environmental clearance was given last March by the Expert Appraisal Committee (EAC) of the Ministry of Environment and Forest. This was challenged in the NGT again, which has now thrown out the challenge.

The result of all these obstacles has been that work, originally scheduled to start in 2012, is yet to take off. The original timeline had envisaged experimental work starting from 2017, later advanced to 2020. It is now unlikely to begin before 2025, even if construction starts next year. Construction of the underground facility would take at least five years.

The project cost, too, likely to escalate. The Union government had, in 2015, approved a budget of Rs 1,583 crore for the project. That budget was based on cost assessments done in 2012. It is estimated the project would now cost at least 25% more than that amount.


More challenges ahead

Bigger uncertainties in terms of government approvals, meanwhile, are still to come. The project applied for clearance from the National Board of Wildlife only in January this year. That approval is still awaited.

Last year, the INO was told it would also need building approval from relevant state government agencies. That building plan is being prepared and an application is likely to be moved later this month. It is unclear how much time it will take to get that approval.

The Tamil Nadu government, which has handed over, free, 26.5 hectares of land in the Bodi West Hills near Pottipuram village in Theni district, has taken its time deciding on approvals for the project. It took two years for the state government to grant approval to a change in land use, from residential to residential-cum-educational, to the project’s control facility in Madurai, and that too after it became evident that the matter was to come up for discussion at the Pragati meeting that Prime Minister Narendra Modi takes with state governments to expedite stalled projects. Again, for three years, the state’s Pollution Control Board did not take any action on the application for the final go-ahead after environmental clearance had been obtained in 2011.

Then there is a pending case in the Madurai bench of Madras High Court, filed in 2015 by MDMK leader Vaiko, who has been opposing the project. The court has passed interim orders asking the INO not to begin any “research work” until final clearance is obtained from the state Pollution Control Board. It is being understood, as of now, that once final clearance is obtained, this interim order will lose its meaning.



Once completed INO will be the largest basic sciences project in India and will have an impact on the emerging high energy physics scenario in the country. People trained at INO will have the expertise to contribute to other high energy and nuclear physics projects around the world. Research and development in neutrino science holds immense potential for India and urgent efforts are needed to implement the project without any further delays. However, while implementing such a mega science project risk assessments and environmental impact assessments should be done to avoid any major threats to the ecology and environment.





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