The Trans Himalayan region of Ladakh is located at the junction of collision between the Indian and Eurasian tectonic plates. The formation of the Himalayas started with the closure of the Tethys ocean around 65 million years ago. The region has a mesmerising landscape with a diversity of geomorphic and geological features. It has a rich and fascinating heritage owing to its unique geographical location. The area comprises wide glacial valleys, majestic mountains, saline and freshwater lakes, sand dunes, and lunar-like surface features. The region’s extraordinary geology has attracted many geoscientists, environmentalists, researchers, and nature lovers from around the world.

Ladakh is a natural laboratory that holds evidence of Himalayan mountain-building process. It has rocks formed at high temperatures and high pressure deep inside the earth that are known as eclogites, which can be observed near Sumdo in Changthang, eastern Ladakh. One can also observe rocks like pyroxenite, serpentinite, harzburgite, lherzolite, dunite, and gabbro, which have crystallised at high temperatures along the Indus and Shayok valleys. As a result of the closure of Tethys ocean, underwater rocks such as ophiolites can be observed in different parts of Ladakh including Nidar and Zildat areas in the east, Shargole in the west, and Spontang, Zangskar in the south. The presence of such rocks provides a unique and rare opportunity to study ocean floor processes. In addition to ophiolites, the erstwhile ocean floor includes fossil-rich limestone, which gives us an opportunity to understand past marine life. This includes fossils of marine life as well as freshwater fossils of plants and animals dating back millions of years.

The Indus river valley is tectonically unstable due to the continued mountain-building process. This has resulted in variations in topography, height of landscape, and sedimentation causing mass movements, and shifting of sediments to valley floors. Owing to these tectonic disturbances, lakes have been known to form due to damming of the Indus for different time spans at various locations in the geological past. In time, sediments would accumulate over the lake floor and once the lake would drain due to outburst floods caused by tectonic activity, the sediments would get redistributed.

These lake deposits are one of the most informative, best-documented, and well-preserved sedimentary archives along the Indus river, which is significant geological evidence of the palaeo-lacustrine environment and a research asset for palaeo-climatic studies in Ladakh. The sequence of lake sediments offers us an opportunity to infer past climatic changes, understand complex geomorphic processes forming a variety of intertwined landforms, and vertical variations in minerals, and to decipher changes in the source of sediments. It also preserves the imprint of past climate and tectonic events that can be used to interpret the climate-tectonic inter-relationship in this geologically active region where glacial and fluvial processes have played an important role in landscape evolution by depositing, blocking, and diverting drainage courses. Such palaeo-lake sites including Spituk (Pethub), Guphuks, Zingchen, Khaltsi, Lamayuru, Achinathang, Hanuthang, Byama, and Akchamal along Indus Valley and Khalsar along Shayok and Tangtse river valleys have immense scientific and educational value.

Granitic bodies extend from the Astor-Deosai-Skardu region to the Lhasa region in Tibet and are evident throughout the Trans Himalayas along a west-to-east axis. These granites are exposed in Ladakh and in geology they are known as Ladakh Granitoid Complex/Ladakh batholith, which consists of a variety of granitic rocks including tonalite, granodiorite, diorite, porphyritic granite, etc—each of which exhibit different textures. These granitic rocks are mineralised with quartz, feldspar, mica, hornblende, tourmaline, etc. The compositional studies of these granites could provide clues to their genetic environment.

Ladakh region is endowed with rich mineral wealth of economic importance. Some of the important minerals that occur in Ladakh are aquamarine beryl crystals in granitic rocks exposed between Hemya and Gaik areas, chromite mineralised in rock bodies of Kyun Tso-Shurok-Sumdo areas in eastern Ladakh and on the way to Marpo-la from Drass in Kargil. Malachite and azurite (copper ores) are present as stains near Basgo in Leh and the confluence of Suru river and Pinjung Nala in Kargil. Gypsum is present in the form of beds and lenses at Phitsi Nala in Zangskar valley, Kargil district, and Puga valley, Leh district. A considerable quantity of magnesite and marble has also been reported from Ladakh. The Himalayan granites possess a high concentration of uranium, thorium, and potassium, which are responsible for the generation of geothermal energy that is evident in the number of hot springs in Ladakh including Panamic, Puga, and Chumathang along with deposits of sulphur, borax, and fluorite mineralisation respectively.

Ladakh is a treasure trove that attracts visitors from around the world to experience and study the remarkable landscapes and landforms that are found in the region. Given its exceptional geology, riches of natural resources, and fragile environment, Ladakh is regarded as an important geo-heritage region that needs urgent attention to prevent possible destruction. These areas are important for school and college-level educational activities as well as scientific studies related to natural hazards, groundwater, environmental changes, geological history, etc. In this context, local communities and the government need to work together to conserve these geological treasures. This will require public awareness, legislation, documentation, and research to systematically preserve these sites while still enabling developmental changes.

Text by Dr. Stanzin Namga and Dr. Meenakshi

Photographs by Stanzin Oldan

Dr. Stanzin Namga is a faculty member at the Department of Geology, University of Ladakh

Dr. Meenakshi is a Postdoctoral Fellow at the Department of Geology, University of Ladakh

Stanzin Oldan is a student at Jamyang School, Leh.

Ladakh is influenced by various geological activities that date back more than 65 million years when the Indian tectonic plate collided with the Asian plate and continues to slide under it. This has led to the creation of the Himalayan ranges and the high altitude Tibetan plateau. The platetectonic collision drained the Tethys sea and created the Indus, Shayok, and Yarlung Tsangpo drainage basins, which are the suture zones between the two tectonic plates. In Ladakh, this includes the Indus-Zangpo suture and the Shayok suture. Hot springs are the most visible manifestation of these sutures or faults. Such hot springs are found across Ladakh with a concentration in Nubra and along the Indus river. In addition, low-intensity earthquakes in the region are another indication of these active tectonic fault lines.
These primal energy resources have emerged as a glimmer of hope for an energy-hungry planet. Modern human civilisation has brought itself to the brink of a climate disaster through the over-exploitation of natural resources, which has fuelled the search for clean and renewable energy. Some of the most promising geothermal fields are located along fractures in the Earth’s crust. The hot spring sites in Ladakh have an unknown potential for geothermal energy resources.
Geothermal energy refers to the heat from the Earth’s mantle, which is transferred to its 40-km thick surface crust. Heat is harnessed from geothermal fluids—essentially water ‘trapped’ deep in fractured rocks that flow into ‘drilled geothermal wells’. In the 1970s, Geological Survey of India explored the geothermal potential of these sites in Ladakh. Presently, the Administration of UT of Ladakh is pursuing a carbon neutral framework for development, which includes the use of renewable energy. An MoU was signed between LAHDC, Leh, Administration of UT of Ladakh, and ONGC Energy Centre Trust (OECT) on 7 February 2021 to establish the Ladakh Geothermal (1 MW) Field Development Facility at Puga. This will be the first geothermal energy power plant in India.

Environmental and wildlife concerns
The Puga Geothermal Field is located inside the Changthang Cold Desert Wildlife Sanctuary. However, there is great demand for power in Ladakh and across the nation, and this pioneering project has been given clearance. In fact, the tripartite MoU was signed before OECT presented the proposal for approval to establish the Ladakh Geothermal (1 MW) Field Development Facility at Puga to the State Board for Wildlife Ladakh (SBWL) on 4 October 2021. Unfortunately, the SBWL approval does not mention required safeguards as the project has been declared as a ‘research project’. Project Manager of OECT, Uday Shankar explained that there is a clause that exempts such projects from wildlife clearances if the area required is less than 5 ha and has a energy generation capacity of 1 MW or less. Several wildlife researchers, including some members of SBWL, spoke on the condition of anonymity. They argued that the geothermal project should be seen in totality with envisaged scaling up, and not in isolation to ‘skirt’ the need for wildlife clearance.
The issue of safeguards is crucial as Puga valley is inhabited by human communities and is located on the Central Asian Flyway (CAF). It is also a nesting site for the black-necked crane (Grus nigricollis). The issue of safeguards and monitoring is very important as the project could cause fluctuations in the water table, impact the hydrology of marshlands, and cause disturbances through its operation and creation of infrastructure such as roads and powerlines. For instance, OECT is building vehicular paths through the marshes in Puga to facilitate the movement of their vehicles. In many places, this has blocked the stream and changed the hydrology of the ecosystem. This could have been addressed with simple eco-friendly designs that would not disrupt the ecological processes of this important wetland.

Blowout and its impacts
A team from Wildlife Conservation and Birds Club of Ladakh (WCBCL) visited the Puga geothermal project site on 16 August 2022 and observed that geothermal fluid from the borehole was being drained directly into Puga stream. They documented the discharge of the dark hot fluid in Puga stream and reported it to Deputy Commissioner, Leh, S. B. Suse who called his deputy, Sub District Magistrate, Nyoma, Jigmet Angchuk and asked for an investigation and immediate cessation of activity. As the media started reporting this incident, the administration called for a review meeting to understand the situation.
Director General of OECT, Ravi [he does not use a last name] addressed the media in Leh on 31 August. He explained that there was a blowout from the borehole at the drilling site. The drilling commenced in July and they discovered a shallow reservoir with high temperatures of 120-130 degrees Celcius at 39m and stopped drilling. He said, “After this, we started cooling the reservoir to continue drilling as the target depth is 1,000m.”
He further explained, “A ‘freak incident’ occurred during the process of cooling the shallow high temperature reservoir after power supply from the grid failed due to heavy rains and the generator set could not be started immediately. This resulted in a delay of 20 minutes before power was restored and the cooling of the reservoir stopped. This is when the blowout occurred. A blowout is an uncontrolled release of steam and hot water from a geothermal borehole.” This is the blowout that WCBCL members witnessed on 16 August and three days later when dark steaming fluid was still flowing out from the borehole.
Furthermore, an ash-like residue has collected in the area after the blowout and it has been left uncovered in the area. A source who inspected the site spoke on the condition of anonymity and said, “The wind is blowing this ash-like substance and polluting the larger landscape. This is very harmful for people and wildlife. It should be covered but no one has looked into this so far.”

Was the blowout discharge hazardous?
OECT has signed an MoU with Iceland Geosurvey (ISOR) for Geothermal Field Development in Ladakh. According to geothermal expert at ISOR, Dadi Thorbjornsson the discharge from the blowout was non-toxic and contained bentonite, cement, rock, and water. However, a paper published in Science of the Total Environment, which assessed the global occurrence of arsenic-rich geothermal fluids and identified them as environmentally hazardous. The paper highlights the importance of safe management of discharge. That said it also reported that geothermal arsenic generally originates in deep reservoirs located several kilometers below the surface. This implies that the discharge from the borehole, which emerged from a depth of 40m, was not hazardous. Project Manager from OECT, Uday Shankar explained that they had carried out tests and found that the concentration of arsenic in the borehole discharge is lower than in water from natural hot springs. ONGC and ISOR thus declared that the discharge in Puga was ‘benign’. However, these test results have not been made public so far.

The need for independent monitoring
ONGC claims that the blowout was a ‘freak incident’ and refuted any claims that it was an accident or caused by a mistake on their part. They claim that the drilling was based on scientific data. However, sources report that the drilling operation has not been carried out in accordance to standard procuedures for a geothermal well. OECT claims that the blowout could not have been prevented though experts claim it could have been aniticipated and its impact could have been contained.
ONGC and ISOR claimed that the geothermal well design is correct and their inability to control the blowout was due to a power failure that disrupted the cooling process. The blowout effectively ‘killed’ the well as OECT has now capped it. It is now planning to conduct exploratory drilling at another location in Puga. Geothermal experts at ISOR claim the earlier design was good and should be replicated with improved power backup systems.
However, the ‘unexpected’ discovery of a reservoir at 40m and the blowout cast doubts over the scientific diligence that should inform the drilling process. It also points to the need for independent scientific review of the project and its processes along with consultations with local stakeholders.
Geothermal energy is said to be cleaner than solar energy as solar cells emit more carbon dioxide in their lifetime than geothermal plants. Geothermal expert and doctoral researcher at Reykjavik University, Iceland, Kunzes Dolma said, “Geothermal requires 20% of the area solar plants require to generate equivalent energy units. Also, 90% of geothermal energy can be converted to usable energy.” She cautioned on the need for strict safeguards for the use of this technology and the risk of energy wastage due to improper implementation and felt that an independent committee of experts should constanly monitor the project.

By Narendra Patil

Narendra Patil is a freelance writer with years of experience in tiger and snow leopard conservation

(An earlier version of this article was published in Down To Earth on 29 August, 2022)

The people of Leh are arguably very religious. There are prayer flags fluttering over mountains, passes, monasteries and Buddhist households. Mosques call the faithful to prayers five times a day from the bank of the Indus to the centre of Leh market. All religions share many basic values be it Buddhism, Islam, Christianity, Sikhism, and Hinduism.

These values are very important in the context of the sweeping changes Ladakh has experienced with the advent of modernity. The purchasing power of locals has grown with the boom in the tourism industry. This has fuelled a culture of over-consumption marked by the desire to have more than one car in each household, multiple business set-ups, live an extravagant life, consume more packaging food and the like.
These cravings are individual choices but it is harming Leh’s ecology. Since 2010, the number of hotels, resorts, camps, restaurants, cafés, and vehicles has increased multi-fold. The President of All Ladakh Hotel and Guest House Association, Leh, Karma Tsering Delek said, “The dramatic increase in domestic tourists has led to an increase in hotels, resorts, and guest houses from 300 in 2010 to 1,200 in 2020.” Such development is often idealised as progress. At the same time, the residents of Leh are often regarded as being environment conscious. Ironically, most residents of Leh do not regard these changes as being problematic. 
Leh is currently characterised by various consumer fetishes. Individual greed and ignorance are the key factors driving this over-consumption. Many correlate possession of material things with happiness without realising that practical frugality has characterised Ladakhi society for hundreds of generations. In addition to its environmental impact, this cycle of consumption also triggers negative emotions such as jealousy, anger, and alienation. “We have all experienced envious neighbours, co-workers, relatives and others who belittle you for not having the same possessions as them,” says Yangchan Dolkar, a resident of Leh town. Unfortunately, the joy experienced from consumption is short-lived and easily replaced by other cravings.

The issue extends beyond social privilege to shared natural resources. For example, we have been exploiting groundwater for many years through bore-wells to accommodate the needs of tourists, residents, building construction, agriculture, to wash automobiles, and to treat sewage. We have forgotten that ground water is an exhaustible resource. The fate of humans and the planet are inextricably inter-linked and interdependent. This means we need to live harmoniously with the environment. We must remember that just because we have the means does not mean we have to consume more. Unfortunately, this sort of greed is very common in Leh town.

Many people wonder if limiting their consumption will make any difference. We forget that every individual choice and action adds up and has an impact on the environment. For instance, a successful social entrepreneur from Shey village has pioneered the use of biodegradable plastic for her bakery products, which is now becoming popular with others.

We need to adopt social, emotional and ethical learning principles in our schools and institutions. We also need to initiate action-oriented change at all levels from the individual to the community to promote environmentally sound lifestyles. This should be institutionalised in both Hill Councils with an Executive Councillor for the environment.

To my fellow Ladakhspa, 
Let’s not steer the conversation by romanticising Leh’s natural beauty,
Let’s not sell the pristine landscape of Ladakh to make easy money,
Let’s not ruin the rich heritage of the mountains,
Don’t just fall for the mountains, save them from falling!

By Dawa Dolma

Dawa Dolma is an independent journalist and environmentalist. She is currently a fellow at TERI

Birds are a fascinating part of our natural heritage. There are various hot-spots for birds in Ladakh that never fail to reward an observant birdwatcher. Unlike known bird-watching hotspots, two interesting avian records from Ladakh, sighted from a remote, rugged, and windy hamlet in eastern Ladakh called Pang. Located at an altitude of around 4,500m above mean sea level, Pang is an important stopover for travellers using the Manali-Leh highway and is about 173 kms from Leh town. It comprises of a few shops and tent accommodations, where most vehicles halt for a break during their long hectic journey.

On 2 July, 2019, one of us (Iqbal Khan) was travelling from Manali to Ladakh for a field visit. During a stop at Pang, an interesting bird was noticed and duly photographed too. The bird was in the company of a flock of yellow-billed chough or Chunka Khaser (Pyrrhocorax graculus) and hill pigeon or Phorgon (Columba rupestris). At first sight, it looked like a juvenile of Eurasian magpie or Kataputit/Khashamburu (Pica pica bactriana) as it hada pied body and a short tail. However, its black and yellow bill suggested that it was not a magpie. I took several photographs and the bird was later identified as a rosy starling Pastor roseus. According to current literature, the rosy starling winters in India and breeds in Central Asia and southeast Europe. It is rare passage migrant in Ladakh. While, there have been a few observation records of them from Ladakh in the past, the July 2019 record seems to be the first photographic record from the region.

This is reminiscent of a similar visit to Ladakh on 2 October, 2016 when one of us (Anil Kumar) was surprised to spot a house crow (Corvus splendens) at Pang. This photographic record seems to be the highest altitude record (4,502m above mean sea level) for the species. Most field guides for birds report that the distribution of house crows is limited to 2,400m above msl. However, there are a few records of house crows from high altitude areas in Himachal Pradesh such asKoksar (3,200 m) and Darcha (3,330m). Previous records from Ladakh are from Karu (3,500 m) and Hanley (4,240 m). There is one record from 15 June, 2012 of a house crow near Tashigang village in Spiti Valley (4,460m above msl).

Given Ladakh’s location at the crossroads of Central Asia, Tibet, South Asia, and West Asia, it is an important staging location for birds migrating between these regions. These two records suggest that fascinating things are constantly taking place around, which we often overlook.

By Iqbal Ali Khan and Anil Kumar

Iqbal Ali Khan (Goshan, Drass) and Anil Kumar are associated with the Northern Regional Centre of Zoological Survey of India, Dehradun

Growing up in Leh, I have always been fascinated by glaciers and snow. As a child, I did not think of issues such as water resources and availability for drinking and irrigation. In the cropping season, we used to source water from the main stream in Leh town. There was sufficient water for everyone due to the presence of well-maintained dZings (reservoirs) in upper Leh, efficient traditional water management systems, and active Chhurpons (water managers). The stream has almost dried up now. Areas that I remember as being lush green with wheat, barley and potato fields are now either barren or have been built over. We used to source our drinking water from a community tap located a kilometre away. In the winter, I remember the difficulties we faced in bringing drinking water home.
Right up till I finished my bachelor’s degree, I remained unaware of that fact that a discipline like cryosphere studies existed that was dedicated to the study of glaciers and snow. With constant support from my family, I managed to get admission to Jawaharlal Nehru University in New Delhi, which remains one of India’s top universities.

It was here that I finally got an opportunity to study glaciers and water resources in Ladakh. Now as I see Ladakh from the perspective of an earth and environmental scientist, I see immense potential for research and intervention especially in the fields of cryosphere, ground and surface water hydrology, wetlands, etc. I am currently pursuing my doctorate on glaciers and water resources in Ladakh and intend to continue working on Ladakh’s cryosphere, water resources and its societal impacts.

I have come to realise how important glaciers are as essential freshwater reserves for inhabitants of high altitude regions as well as lowland plains. Ladakh is a heavily-glaciated region in India and is home to nearly 5,000 glaciers, which accounts for about 50% of all glaciers in the country and covers an area of about 3,200 sq km. It is very difficult to study all the glaciers directly. Researchers are forced to use remote sensing technology, mathematical modelling and indirect techniques to study glacial systems on a larger extent. Such studies require ground-based data or ground-truthing for calibration and validation.

One such field-based measurement is currently being carried out by us in Leh. We are a team of glaciologists from Jawaharlal Nehru University, New Delhi led by Prof. AL. Ramanathan. We recently published the findings of our research in the Journal of Glaciology. Our research focuses on the Stok catchment in Leh district and has been underway since 2014 and continues. The research focuses on studying the health of the glacier by measuring glacier mass balance, water resources, and associated changes in the past, present and near future. Mass balance quantifies gain/loss of ice or water from a glacier each year.

The data we have collected so far suggests that glaciers around Leh are losing mass at a rate of 0.4 metres water equivalent per year or mw.e. a^-1, which is similar to other Himalayan glaciers whose average mass balance rate is around -0.5 m w.e. a^-1 per year. Our data includes measurements over five years and a historical analysis of three periods between 1978 and 2019. We found that the glacier was healthy in the period from 1978 to 1989 due to abundant precipitation. In this period, the glacier gained and lost mass in almost equal amount,which ensured that it remained relatively stable. However, in the decade from 1998 to 2009 the glacier suffered severe mass loss due to comparatively little precipitation and drought conditions. In the present decade from 2011 to 2019, the glacier has continued losing mass at a moderate rate.

The mass that glaciers lose through melting in summer are mainly offset by accumulation in the winter months. This winter precipitation is very significant for the health of a glacier and Stok is no exception. We have estimated that about 27% of excess precipitation is required to compensate for the glacial mass loss due to a 1 degree Celsius rise in temperature.

According to our research, the average mass balance for the last five hydrological years was 0.4m w.e. per year. This means that 0.4 m or 40 cm water equivalent of ice each year has been lost from the surface of Stok glacier. A lot of these numbers seem rather abstract till they are put into context to understand them in everyday terms. For instance, the figure mentioned above is equivalent to Stok glacier losing around 30,000 water tankers of 10,000 litres capacity each year since 2014.Similarly, the amount of water that Stok glacier loses in one year is enough to support Stok village for around 10 years.Finally, the volume of water that Stok glacier holds is sufficient to support the entire population of Ladakh region for about five years. Here we have assumed water consumption at the rate of 60 litres per person per day, using the 2011 census figures and excluding irrigation needs.

This gives us an idea of the amount of freshwater reserves that we have in Ladakh as Stok glacier does not represent even one percent of total glacier volume in the region. Though, we cannot harvest the entire meltwater from these glaciers for reasons ranging from topography, remoteness, lack of technology etc.,we can optimise the manner in which we use water. The simplest way is to rejuvenate and increase the capacity of traditional water management systems, while also making the best use of available water. There have been some innovations in water management techniques including artificial glaciers, ice stupas etc, whose performance need to be critically evaluated in relation to the resources they require. The successful ones must be encouraged and replicated.

Climate change and global warming is real and happening. It has observable effects around the globe and Ladakh is no exception. Glaciers in Ladakh are shrinking, temperature is rising, less snow and more rain is happening etc. These effects are due to a global phenomenon and cannot be stopped or reduced on a regional level. Instead we can educate the people to reduce our individual, societal and regional carbon footprint. In addition, we must also prioritise climate change resilient systems and adaptation strategies to mitigate the impacts of climate change.Together, we can make a significant contribution to the scientific community and serve the people of Ladakh and humanity at large.

Photographs and text by Mohd Soheb

Mohd Soheb is a Glaciologist at Jawaharlal Nehru University, New Delhi, India

An annular solar eclipse occurred on 21 June and people were able to witness it from different parts of the country. With some advance preparation, I was able to capture the whole sequence of the annular solar eclipse in the sky above the Himalayan Chandra Telescope at the Indian Astronomical Observatory in Hanle, eastern Ladakh.

For this shot, I used a Sony A7s2 Rokinon 14mm @f/4 shutter speed of 1/4000s x 80 subs with an ISO setting of 400 for the eclipse timeline. The foreground was photographed without a filter at 1/40sec shutter speed and an ISO setting of 200. Each exposure was timed at an interval of 150 seconds A few passing clouds did dim the eclipse after the peak of the eclipse.

It is good to see a growing interest in astronomy. I base this observation on the fact that the Indian Astronomical Observatory had broadcast the annular solar eclipse live over YouTube. This broadcast attracted several thousand people who tuned in to watch the solar eclipse with a peak of 4,500 viewers at one point.

By Dorje Angchuk

Dorje Angchuk is an engineer and astro-photographer

We are currently grappling with electromagnetic and light pollution in addition to other forms of pollution. Each of these forms of pollution have a similar negative impact on our health and environment. While the world at large is taking significant action to reduce the exploitation of nature and reduce pollution, we need to expand these efforts to also address the issue of light pollution.

Current scientific literature suggests that exposure to artificial light at night poses significant risks to human health as it disrupts our sleep patterns. At the same time, the lack of lighting in urban areas has a high correlation with high crime rates. The main challenge here is to limit people’s exposure to artificial light at night while still providing adequate lighting to ensure safety and security.

In this context, unshielded lights remain one of the main challenges. Unshielded lighting wastes illumination as it spreads light over a large area, which is unnecessary. This leads to light pollution, which reduces visibility of stars in the night sky. Outdoor lights should be properly shielded and only used when needed. Furthermore, shielded lights are not only more efficient in providing targeted illumination but also consume less electricity.

Light pollution also has a negative impact on the environment, especially wildlife. Light interferes with the natural day-night cycle i.e. circadian rhythm. Plants use photosynthesis to prepare food during the day and rest at night, similar to humans and other diurnal animals and birds. In contrast, nocturnal animals and birds are active at night and rest during the day. Light pollution wrecks havoc with this natural cycle. Urban lighting has been correlated with the disappearance of many species, and also interferes with the migration of birds and the movement of turtles.

In addition, light pollution also prevents us from exploring the wonders of the universe. Our ancestors have looked skywards since the birth of time in wonderment of the stars, planets and other heavenly bodies that light up the night sky, especially from our own galaxy, the Milky Way. The wonders of the night sky have inspired philosophers, scientists and poets alike through the course of history. However, over the last 100 years or so we have started introducing artificial lights that have prevented us from seeing the night sky for the first time in history. Illumination from urban areas is very intense and light pollution spreads over hundreds of kilometres from their points of origin.

Astronomy is one of the oldest sciences that started a study of objects in the night sky. While astronomers have worked from human settlements for several millennia, increasing light pollution over the last century has pushed them to remote areas where population is sparse and development is limited. Astronomers study the universe by collecting faint light emitted by distant celestial objects. In order to collect such data, astronomers have been forced to establish observatories in remote areas ‘untouched’ by human ‘civilisation’ where the sky has not been polluted by light like our urban areas.

Astronomers have known for several decades that high altitude cold desert conditions like Ladakh have many clear nights and days. Such areas provide ideal conditions for astronomical studies. In the mid-1980s, there was a national effort to identify suitable sites for astronomical studies in India. The Indian Institute of Astrophysics conducted a detailed study of meteorological conditions over the Indian subcontinent and visited six prospective sites. At the end of this study, in 1994 Hanle valley in Changthang, eastern Ladakh was identified as the best site for astronomy in India.

The Indian Astronomical Observatory (IAO) was established on Digpa Ratsa-ri, Hanle in 1997 where the two metre-aperture Himalayan Chandra Telescope was installed in 2000. In addition to astronomy, the observatory has also facilitated studies in geophysics, atmospheric trace gases and aerosols. This has generated employment in Ladakh and created opportunities for Ladakhis to contribute to scientific development through these projects.

Today, Hanle valley is recognised as one of the best sites in the world for astronomical studies along with Mauna Kea Observatory in Hawaii, observatories in the Andean mountains of Chile, and European facilities in the Canary Islands, Spain. The establishment of IAO spurred Chinese astronomers to study sites in their territory and they identified Ngari prefecture in the Tibetan Autonomous Region, adjacent to Hanle, as the best site. An observatory has now been established in Ali in Ngari prefecture along with a dark sky sanctuary around it.

Over the last three decades, Hanle valley has experienced significant changes. Khaldo village near the IAO is one of the fastest-growing hamlets in the Changthang region. In 1994, there were very few settlements around Hanle. As IAO became operational, local settlements also increased in the immediate vicinity. In due course, the number of tourists visiting the valley has increased along with resulting development of tourist infrastructure. Currently, there are five to six commercial establishments in Hanle in the form of guest houses and home stays. While the current growth is concentrated around IAO, future projections suggest significant geographical expansion. Current models suggest that such developmental activities will increase light pollution, which will have a detrimental effect on the astronomical merits of the observatory site.

The modest telescope at Hanle has helped Indian astronomy advance in leaps and bounds since its installation. More facilities are being developed at Hanle that will put IAO on the global map of major astronomical infrastructure. It is hence necessary to protect the area from light pollution like other major astronomical observatories around the world.

In this regard, we must implement a dark sky sanctuary model in Hanle to cover the entire valley from Rongo village to Nilamkhul Plains and the surrounding mountains. Dark sky sanctuaries are generally established in such remote areas around astronomical observatories. In addition to promoting astronomy, such a sanctuary also provides opportunities to tourists and residents to appreciate the night sky as their forefathers, which is impossible in urban areas due to intense light pollution. It also provides a healthy developmental model for biodiversity and human communities.

There is a false notion that the preservation of dark skies requires everyone to turn their lights off and compromise on their security and developmental aspirations. Good lighting policies that protect dark skies also enhance security and support people’s aspirations. They focus on reducing glare, attenuating harsh lighting that creates shadows and focus on targeted lighting and use of adaptive technology to provide lighting solutions. A dark sky sanctuary promotes proper illumination where and when it is needed without wasting energy and polluting other areas, especially the night sky, which does not require illumination.

Reducing artificial illumination at night will also benefit wildlife in the Changthang Wildlife Sanctuary. It will ensure that animals, birds, and humans follow the natural circadian rhythm. The restrictions and improved management of artificial lights will help improve the quality of life for wildlife and humans in the area.

The dark sky sanctuary model provides an alternative to the wasteful and unsustainable urban model of development. It promotes the use of energy-efficient lighting and appropriate shades to illuminate only the required area. Similarly, simple measures such as appropriate curtains over windows can ensure that light does not escape from homes. Outdoor lights can be switched off when everyone is indoors. While night driving is best avoided in a wildlife and dark sky sanctuary, the roads can be painted with fluorescent paints and retro-reflectors to ensure that people can drive with parking lights in case of an emergency. The use of dark sky-compliant lighting will also ensure enormous savings in terms of energy consumption and tariff.

The dark sky sanctuary can also be linked to tourism to create opportunities to educate people about the benefits of dark sky-compliant lighting and lifestyle. Numerous dark sky preserves, sanctuaries, and parks have been established around the world. Dark sky protection has been enforced around most astronomical observatories in the world with an average radius of 30 km while China has established a 2,500 sq km dark sky park in Ngari prefecture around its observatory in Ali.

By preserving the natural conditions of day and night and keeping artificial illumination to the minimum, a dark sky sansctuary enables astronomers to undertake scientific research. They are able to detect the faintest levels and highest sensitivities possible from the Earth’s surface. In addition to environmental and health benefits, such a sanctuary must also help local communities (and tourists) observe and appreciate celestial objects. Facilities can be developed to provide education and awareness on astronomy, ecology and culture through public observatories, museums and planetarium with strict regulation on use of artificial lights. Ethno-tourism can be combined with astro-tourism and eco-tourism to ensure that tourists learn practical measures for sustainable living and locals benefit economically. In time, these strategies to manage light pollution can also be extended to urban areas to improve their night sky visibility.

We must appreciate dark skies and promote dark sky sanctuaries as unique community assets and make them an integral part of our local and national heritage. In addition to the scientific benefits, such an initiative must benefit local communities by creating educational and economic opportunities. Local communities must also be educated and receive incentives to be a part of such efforts.

Photographs, illustrations and text by Dorje Angchuk

Dorje Angchuk is an engineer and astro-photographer