The Himalayas and Northern Mountains

In our previous chapter, "States and Union Territories of India," we looked at the political lines drawn by humans to organize the country. Now, we are going to erase those human-made borders and look at the lines drawn by nature. We are diving into the physical geography of India, starting with the magnificent crown at the top of the map: The Northern Mountains.

If you want to truly understand India's climate, its major river systems, its agriculture, and even its historical defense strategies, you have to understand the Himalayas. They are not just a wall of rock; they are a complex, living, breathing geological system.

Before we zoom into the mountains, let us quickly set the stage. Geographers generally divide the landmass of India into six major physical divisions:

1. 1The Northern Mountains (The Himalayas and Trans-Himalayas)
2. 2The Northern Plains (The flat, fertile lands fed by Himalayan rivers)
3. 3The Peninsular Plateau (The ancient, stable landmass of southern India)
4. 4The Indian Desert (The Thar Desert in the west)
5. 5The Coastal Plains (The eastern and western coastlines)
6. 6The Islands (Andaman & Nicobar, and Lakshadweep)

In this chapter, we are focusing entirely on the first division: The Northern Mountains. We will break down how they were formed, explore their parallel ranges from north to south, travel through them from west to east, and finally, map out the crucial mountain passes that allow humans to cross them.

How the Himalayas Were Born

To understand the structure of the Himalayas, you first need to know how they got there. The Himalayas are classified as young fold mountains.

Millions of years ago, the landmass that is now India was an island situated far to the south, off the coast of Australia. It broke off and began a long, slow journey northward. Between this advancing Indian landmass and the massive Eurasian landmass to the north lay a vast, shallow body of water called the Tethys Sea.

Over millions of years, rivers from both landmasses dumped massive amounts of sediment (mud, sand, and gravel) into the Tethys Sea.

Eventually, the Indo-Australian tectonic plate crashed into the Eurasian tectonic plate. Imagine pushing a thick rug against a wall. What happens? The rug buckles, folds, and rises upward. This is exactly what happened to the sediments at the bottom of the Tethys Sea. The immense pressure of the collision squeezed the seabed, folding it up into the sky to create the highest mountain range on Earth.

This is why, today, climbers who reach the summit of Mount Everest—the highest point on land—often find fossilized seashells and marine life in the rocks. The top of the world was once the bottom of the ocean.

Because the tectonic plates are still pushing against each other, the Himalayas are still growing taller by a few millimeters every year. This ongoing tectonic activity is also why the entire Himalayan region is highly prone to earthquakes.

The Structure of the Northern Mountains

When we look at a map, the Northern Mountains look like a single, chaotic jumble of snow and rock. But they are actually highly organized.

Think of the Northern Mountains as a massive crescent or an arc stretching for about 2,400 kilometers from the Indus River gorge in the west to the Brahmaputra River gorge in the east.

Geographically, we divide this massive mountain system into two main categories based on their location and age:

1. 1The Trans-Himalayas: The ranges lying to the north of the main Himalayas.
2. 2The Himalayas Proper: The three main parallel ranges that make up the core of the mountain system.

Let us explore them one by one, starting from the extreme north and moving southwards.

1. The Trans-Himalayas (The "Beyond" Himalayas)

The word "Trans" means across or beyond. The Trans-Himalayas are the mountain ranges located immediately to the north of the Great Himalayan range.

Here is a crucial fact: The Trans-Himalayas are actually older than the main Himalayas. They were formed before the final, massive collision that created the main Himalayan peaks. Much of this region lies in the Tibet Autonomous Region of China, which is why it is sometimes called the Tibetan Himalaya, but significant portions lie within the Indian Union Territories of Ladakh and Jammu & Kashmir.

The Trans-Himalayan region consists of three major mountain ranges. From North to South, they are:

The Karakoram Range

This is the northernmost range of India, acting as a natural boundary between India and Central Asia. It is a region of towering peaks and massive glaciers.

• Key Peak: The Karakoram is home to K2 (also known as Godwin Austen). Standing at 8,611 meters, K2 is the second-highest mountain in the world and the highest peak of India. It is located in Pakistan-occupied Kashmir (PoK), which is an integral part of India.
• Glaciers: This range houses some of the largest glaciers outside the polar regions, most notably the Siachen Glacier, which is also known as the world's highest battlefield.

The Ladakh Range

Lying to the south of the Karakoram is the Ladakh range. It is a high-altitude cold desert, characterized by barren, rugged terrain with very little vegetation due to the lack of rainfall (as it lies in the rain shadow of the Greater Himalayas).

The Zanskar Range

South of the Ladakh range lies the Zanskar range. The mighty Indus River flows exactly between the Ladakh and Zanskar ranges, cutting a deep valley through the mountains.

2. The Himalayas Proper: The Three Parallel Ranges

South of the Trans-Himalayas lies the main Himalayan mountain system. Unlike the Trans-Himalayas, which are somewhat broken, the main Himalayas consist of three distinct, continuous, parallel ranges running from west to east.

Imagine three massive steps leading down from the Tibetan plateau to the Indian plains.

Step 1: The Greater Himalayas (Himadri)

This is the northernmost, highest, and most continuous of the three parallel ranges. It is the "core" of the Himalayas.

• Also known as: Inner Himalayas or Himadri (meaning "abode of snow").
• Height: It has an average elevation of about 6,000 meters.
• Characteristics: Because of its extreme height, the Himadri is permanently covered in snow and ice. It contains all the most famous, towering peaks of the Himalayan system. The core of this range is made of hard rocks like granite.
• Key Peaks:
• Mount Everest: The highest peak in the world (8,848.86 meters). It is located in Nepal (where it is called Sagarmatha).
• Kangchenjunga: Standing at 8,586 meters, it is located on the border of Sikkim (India) and Nepal.
• Other notable peaks include Makalu, Dhaulagiri, Nanga Parbat (the western anchor of the Himalayas), and Namcha Barwa (the eastern anchor).

Step 2: The Lesser Himalayas (Himachal)

Lying to the south of the Himadri is the middle range, known as the Lesser Himalayas.

• Also known as: Middle Himalayas or Himachal.
• Height: The altitude varies between 3,700 and 4,500 meters.
• Characteristics: This range is highly rugged and heavily forested. While the Himadri is a harsh, frozen world, the Himachal range is famous for its pleasant climate during the summer. This is the range where almost all of India's famous northern hill stations are located—Shimla, Mussoorie, Nainital, Ranikhet, and Darjeeling.
• Important Sub-Ranges: The Lesser Himalayas are not a single unbroken wall; they consist of several important local ranges.
• Pir Panjal Range: The longest and most important range of the Lesser Himalayas, located mostly in Jammu & Kashmir.
• Dhauladhar Range: Prominent in Himachal Pradesh.
• Mahabharat Range: Located in Nepal.
• Famous Valleys: Between the Greater Himalayas (Himadri) and the Lesser Himalayas (Himachal) lie some of the most beautiful valleys in the world, including the Kashmir Valley, the Kullu Valley, and the Kangra Valley.

Step 3: The Outer Himalayas (Shiwaliks)

This is the southernmost range of the Himalayas, acting as the foothills before the mountains flatten out into the Northern Plains.

• Also known as: The Outer Himalayas.
• Height: This is the lowest range, with an average altitude of just 900 to 1,100 meters.
• Characteristics: Unlike the Himadri (solid granite) or the Himachal (compressed rocks), the Shiwaliks are made entirely of unconsolidated sediments—gravel, mud, and soft rocks brought down by the rivers flowing from the higher ranges. Because they are made of loose material, the Shiwaliks are highly prone to landslides and heavy soil erosion during the monsoon season.

Regional Divisions of the Himalayas (West to East)

So far, we have sliced the Himalayas horizontally (North to South). But geographers also slice the Himalayas vertically (West to East) to study regional differences.

Sir Sydney Burrard, a prominent geographer, classified the Himalayas into four regional divisions based on the major river valleys that cut through them. You must know which rivers border which region.

Let us look at these briefly:

1. 1Punjab / Kashmir Himalayas: The westernmost section between the Indus and Satluj rivers. A large portion of this lies in Jammu & Kashmir and Himachal Pradesh.
2. 2Kumaon Himalayas: Lying between the Satluj and Kali rivers, this section is mostly in Uttarakhand. It is home to peaks like Nanda Devi and Kamet, and the sources of the Ganga (Gangotri) and Yamuna (Yamunotri) rivers.
3. 3Nepal Himalayas: The longest section, lying between the Kali and Teesta rivers. It contains the tallest peaks, including Everest and Kangchenjunga.
4. 4Assam Himalayas: Lying between the Teesta and Dihang (Brahmaputra) rivers, covering parts of Sikkim, Bhutan, and Arunachal Pradesh.

The Purvanchal (Eastern Hills)

What happens when the Himalayas reach the eastern edge of India at the Brahmaputra gorge? They don't just stop. The mountain chain takes a sharp southward bend, running along India's eastern border with Myanmar.

These eastern extensions are called the Purvanchal or Eastern Hills. They are much lower in height compared to the main Himalayas and are covered in dense tropical forests. They comprise several local hills, such as the Patkai Bum, Naga Hills, Manipur Hills, and Mizo Hills.

Important Mountain Passes (The Gateways)

Mountains are massive barriers to trade, travel, and military movement. To cross them, humans rely on passes—natural gaps or lower points in a mountain ridge. In the Tibetan language, the word for pass is La. Therefore, saying "Khardung La Pass" is technically saying "Khardung Pass Pass," but it is common usage.

Mountain passes are heavily tested in exams. You need to know which state or Union Territory they are in, and ideally, what they connect.

Passes in Ladakh

• Karakoram Pass: A historical trade route connecting Ladakh to the Xinjiang region of China.
• Khardung La: One of the highest motorable roads in the world, connecting Leh to the Nubra Valley.
• Zoji La: A crucial strategic pass in the Greater Himalayas that connects Srinagar to Leh. It remains closed during harsh winters due to heavy snowfall.
• Aghil Pass: Located in the Karakoram range, connecting Ladakh with the Xinjiang province of China.

Passes in Jammu & Kashmir

• Burzil Pass: Connects the Kashmir Valley with Gilgit (in PoK).
• Banihal Pass: Located in the Pir Panjal range, this is the vital link connecting Jammu to Srinagar. The famous Jawahar Tunnel was constructed under this pass to ensure year-round connectivity.

Passes in Himachal Pradesh

• Rohtang Pass: Connects the Kullu Valley with the Lahaul and Spiti Valleys. It is famous for its heavy tourist traffic.
• Bara Lacha La: Connects Lahaul district in Himachal Pradesh to Leh in Ladakh.
• Shipki La: A very important pass on the India-China border. The Satluj River enters India from Tibet through this pass.

Passes in Uttarakhand

• Lipulekh Pass: A highly strategic pass located at the tri-junction of India, Nepal, and China (Tibet). It is famously used by pilgrims traveling to Mount Kailash and Lake Mansarovar.
• Mana Pass and Niti Pass: Both connect Uttarakhand with Tibet.

Passes in Sikkim

• Nathu La: A major trading border post between India and China. It was closed after the 1962 Sino-Indian War and reopened in 2006.
• Jelep La: Connects Sikkim with the Chumbi Valley in Tibet.

Passes in Arunachal Pradesh

• Bomdi La: Connects Arunachal Pradesh with Lhasa, the capital of Tibet.
• Diphu Pass: Located at the tri-junction of India, China, and Myanmar.

Significance of the Himalayas

Before we wrap up, it is worth asking: why do the Himalayas matter so much to India?

1. 1Climatic Divide: The Himalayas act as a massive climate wall. In the winter, they block the freezing, dry winds blowing from Central Asia and Siberia, keeping the Indian subcontinent relatively warm. In the summer, they trap the moisture-laden Southwest Monsoon winds, forcing them to shed their rain over India rather than blowing away into Central Asia. Without the Himalayas, India would be a cold, dry desert.
2. 2Source of Rivers: The glaciers of the Himalayas are the birthplace of India's great perennial river systems—the Indus, the Ganga, and the Brahmaputra. These rivers bring life, water, and fertile soil to the Northern Plains.
3. 3Defense: Historically, the towering peaks have acted as an impenetrable natural fortress, protecting the Indian subcontinent from invasions from the north.

Quick Revision

Scan these high-yield points before your exam to lock in the most frequently tested facts:

• Formation: The Himalayas are young fold mountains formed by the collision of the Indo-Australian and Eurasian tectonic plates, pushing up the Tethys Sea.
• Trans-Himalayas: Older than the main Himalayas. Ranges from North to South: Karakoram, Ladakh, Zanskar.
• Highest Peaks: K2 (Godwin Austen) is the highest peak of India (in Karakoram, PoK). Kangchenjunga is the highest peak in undisputed Indian territory (in Sikkim).
• Three Parallel Ranges:
• Himadri (Greater): Highest, core is granite, permanently snow-capped.
• Himachal (Lesser): Rugged, home to hill stations (Shimla, Mussoorie) and the Pir Panjal range.
• Shiwaliks (Outer): Lowest, made of loose river sediments, prone to landslides. Home to flat valleys called Duns (Dehradun).
• River Boundaries:
• Indus to Satluj = Punjab/Kashmir Himalayas
• Satluj to Kali = Kumaon Himalayas
• Kali to Teesta = Nepal Himalayas
• Teesta to Dihang = Assam Himalayas
• Key Passes: Zoji La (Srinagar to Leh), Banihal (Jammu to Srinagar, Jawahar Tunnel), Shipki La (Satluj enters India), Lipulekh (Tri-junction in Uttarakhand), Nathu La (Sikkim).