Indian Himalayan Region

The Indian Himalayan Region (IHR) is the part of the Himalayan mountain system that lies inside India. It stretches about 2,500 km, from Jammu and Kashmir and Ladakh in the west to Arunachal Pradesh in the east. It covers about 16.2% of India's land area and spreads across 13 States and Union Territories. The IHR is very valuable, because it gives India water, forests, wildlife and a natural wall on the northern border. It is also very fragile, because it is young, steep, earthquake-prone and warming fast.

Which States and UTs make up the IHR?

There are 13 of them:

• Jammu and Kashmir, Ladakh, Himachal Pradesh, Uttarakhand (Western Himalaya)
• Sikkim and the hill districts of West Bengal (Darjeeling and Kalimpong) (Central-Eastern Himalaya)
• Arunachal Pradesh, Assam (hill districts), Meghalaya, Nagaland, Manipur, Mizoram, Tripura (Eastern Himalaya and north-eastern hills)

According to the 2011 Census, about 4.68 crore people lived in the IHR. That is about 3.87% of India's population, spread over more than 61,000 villages and about 540 towns.

How did the Himalayas form?

The Himalayas are fold mountains. Fold mountains form when two huge plates of the Earth's crust push into each other and the rock layers bend and rise, like a carpet pushed against a wall. Around 50 million years ago, the Indian Plate, moving north, collided with the Eurasian Plate. That collision is still going on. The Indian Plate keeps pushing north at about 5 cm per year. This is why the Himalayas are still rising and why earthquakes are common there.

What are the main ranges?

From south to north, the Himalayas have three parallel ranges:

• Shiwaliks (Outer Himalaya): the lowest and youngest hills, made of loose, soft material. They erode easily.
• Lesser Himalaya (Himachal): the middle range, home to hill towns like Shimla, Mussoorie, Nainital and Darjeeling.
• Greater Himalaya (Himadri): the highest range, with peaks like Kangchenjunga and Nanda Devi, and most of the glaciers.

Beyond these lies the Trans-Himalaya (ranges such as the Karakoram and Ladakh ranges).

Why is the IHR so important?

• Water tower of India: The Himalayan glaciers and snow feed the Indus, Ganga and Brahmaputra river systems. Hundreds of millions of people downstream depend on them for drinking water, farming and power. This is why the Himalaya, with the Tibetan Plateau, is often called the "Third Pole": it holds the largest store of ice outside the North and South Poles.
• Biodiversity: Two of India's four global biodiversity hotspots, the Himalaya and Indo-Burma, cover parts of the IHR.
• Climate shield: The mountains block cold winds from Central Asia in winter and trap monsoon winds, which then drop rain over north India.
• Strategic wall: The IHR borders Pakistan, China, Nepal, Bhutan and Myanmar. Roads and tunnels here matter for national defence.
• Culture and livelihood: Pilgrimage centres (Badrinath, Kedarnath, Amarnath), tourism, horticulture and hydropower support the local economy.

Why is the IHR so fragile?

• Young and loose rock: Many slopes are made of broken, weak material. Cutting into them for roads easily triggers landslides.
• Earthquake risk: India's revised earthquake design code (IS 1893:2025) by the Bureau of Indian Standards created a new highest category, Zone VI, which covers the entire Himalayan arc. Earlier, Zone V was the highest.
• Fast warming: Glaciers are shrinking, snow cover is falling and permafrost is thawing. This creates new glacial lakes and weakens high slopes.
• Extreme rain: Cloudbursts (very heavy rain in a small area in a short time) cause flash floods and debris flows.
• Heavy human pressure: More roads, tunnels, dams, hotels and tourists than the land can safely bear.

Major disasters that show the fragility

• Kedarnath, June 2013: extreme rain and a flood from the Chorabari lake area devastated the Kedarnath valley in Uttarakhand.
• Chamoli, February 2021: a rock-ice avalanche from Ronti Peak caused a debris flow that killed or left missing more than 200 people and damaged two hydropower projects.
• Joshimath, January 2023: cracks spread across houses and roads in this Uttarakhand town. As far back as 1976, the Mishra Committee had warned that the town sits on old landslide debris and had advised limits on heavy construction.
• South Lhonak, October 2023: a glacial lake burst in Sikkim and destroyed the Teesta-III dam at Chungthang.
• Silkyara, November 2023: part of a road tunnel on the Char Dham route in Uttarkashi collapsed on 12 November 2023, trapping 41 workers. All were rescued after 17 days.

What is "carrying capacity"?

Carrying capacity is the largest number of people, vehicles and buildings an area can support without damaging its land, water and forests. Think of a lift that is rated for 8 people: if 15 people get in, it may break. In 2023, a petition in the Supreme Court (Ashok Kumar Raghav v. Union of India) asked for carrying capacity studies of the Himalayan States.

The Union Environment Ministry proposed that each of the 13 Himalayan States set up a committee under its Chief Secretary, and that a technical committee headed by the Director of the G.B. Pant National Institute of Himalayan Environment examine their studies.

India's institutions and policies for the IHR

• National Mission for Sustaining the Himalayan Ecosystem (NMSHE): one of the eight national missions under the National Action Plan on Climate Change (launched 30 June 2008). It is coordinated by the Department of Science and Technology. It aims to keep assessing the health of the Himalayan ecosystem and its glaciers.
• G.B. Pant National Institute of Himalayan Environment: a research institute under the Union Environment Ministry, based at Kosi-Katarmal, Almora (Uttarakhand). It studies Himalayan ecology and guides development planning.
• Char Dham road case (December 2021): On 14 December 2021, the Supreme Court allowed the Defence Ministry's request to widen three strategic Char Dham feeder roads to a double lane with paved shoulder (about 10 m tarred width). It cited national security, and set up an oversight committee headed by retired Justice A.K. Sikri to watch environmental safeguards.
• National GLOF Risk Mitigation Programme (2024): for glacial lake monitoring and early warning in four Himalayan States.

Commonly confused concepts

• Indian Himalayan Region vs Hindu Kush Himalaya (HKH): The IHR is only the Indian part. The HKH is the larger mountain system across eight countries: Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan. The International Centre for Integrated Mountain Development (ICIMOD), based in Kathmandu, works on the HKH.
• Greater Himalaya vs Trans-Himalaya: The Greater Himalaya has the highest peaks. The Trans-Himalaya lies north of it (Karakoram, Ladakh, Zanskar ranges) and is drier, a cold desert.
• Carrying capacity vs Environmental Impact Assessment (EIA): EIA checks one project at a time. Carrying capacity looks at the total load an entire area can bear from all projects together.
• Landslide vs land subsidence: In a landslide, a slope moves down sideways. In land subsidence, the ground sinks down, as seen in Joshimath.

Issues, criticism and the way forward

• Project-by-project approval: Each road, dam or hotel is cleared alone. Experts say the combined effect of many projects in one valley is often ignored.
• Planning for the past climate: Infrastructure is designed using old rainfall and temperature data, while the mountains are changing fast.
• Development vs ecology: The government stresses that roads, tunnels and hydropower are needed for border security, connectivity, jobs and clean energy. Environmental groups and many scientists argue that unchecked construction is raising disaster risk. Both concerns are real, which is why balanced planning is needed.
• Tourism pressure: Unregulated tourism and pilgrimage crowds strain water, waste systems and fragile slopes.
• Way forward: Experts suggest carrying capacity studies for each valley, risk-based planning that considers future climate, hazard zoning (marking no-build zones), early warning systems for glacial lakes and cloudbursts, better slope engineering, and involving local communities in decisions.

Concepts to Know

• Tectonic plate: A giant slab of the Earth's outer shell. Plates move slowly and, where they collide, they build mountains and cause earthquakes.
• Biodiversity hotspot: A region with very many species found nowhere else, which has also lost at least 70% of its original natural vegetation. India has parts of four: Himalaya, Indo-Burma, Western Ghats and Sri Lanka, and Sundaland.
• Cloudburst: Extremely heavy rain falling over a small area in a very short time (the India Meteorological Department uses about 100 mm or more in an hour). It causes sudden floods in hills.
• Hazard zoning: Dividing land on a map by how dangerous it is, so that building is limited in the riskiest areas.