The Indus River System

Start at the source and the numbers. The Indus is the westernmost of the Himalayan rivers in India, and it is one of the largest river basins in the world.

1. Where does the Indus rise, and where does it end?

NCERT says the Indus rises from a glacier near Bokhar Chu in the Kailash range of Tibet. The spot lies at about 4,164 metres. In Tibet the river is called Singi Khamban, or Lion’s mouth. Lake Manasarovar, a high-altitude lake, lies close to Mount Kailash.

The river flows first through Ladakh, then crosses into Pakistan. It finally empties into the Arabian Sea, east of Karachi.

2. How long is the Indus, and how large is its basin?

NCERT Class XI gives the Indus a total length of 2,880 km. Of this, 1,114 km lies in India. NCERT Class IX gives a rounder figure of about 2,900 km. Use the figure your question names.

The whole basin covers about 11,65,000 square kilometres. India holds about 3,21,289 square kilometres of it. That is a little over a quarter of the basin, so most of the basin lies outside India.

3. What are a drainage basin and a water divide?

Small streams from different directions come together to form a main river. The area drained by a single river system is called a drainage basin.

An elevated area, such as a mountain or an upland, separates two drainage basins. Such an upland is called a water divide.

4. Which states and Union Territories does the Indus basin cover in India?

The Central Water Commission lists the Indian share of the basin state by state. Jammu and Kashmir holds the largest part, at 1,93,762 square kilometres. Himachal Pradesh has 51,356 and Punjab has 50,304. Rajasthan has 15,814 and Haryana has 9,939. Chandigarh has 114.

NCERT says the Indus itself flows in India through the Union Territories of Ladakh and Jammu and Kashmir. The rest of the basin belongs to the tributaries.

• Mountain part: Ladakh, Jammu and Kashmir, and Himachal Pradesh.
• Plains part: Punjab, Haryana and Rajasthan.

5. What is an antecedent river, and is the Indus one?

An antecedent river is a river that existed before the mountain range it now cuts through was formed. The Indus is called an antecedent river. That means it already existed before the Himalayas rose around it.

Britannica says the Indus is probably older than the mountains it crosses. The Himalayas rose slowly. So the old rivers kept flowing in their channels and cut their valleys deeper as the land rose.

NCERT names the Satluj, the Kosi and the Subansiri as antecedent rivers. NCERT also says the Indus cuts across the Ladakh range in a spectacular gorge. The Brahmaputra shares the same history on the other end of the Himalayan arc.

Before it reaches Punjab, the Indus collects many mountain tributaries. Some are in India, and some lie across the border.

6. What route does the Indus take from Ladakh to the plains?

After rising in Tibet, the Indus flows northwest between the Ladakh and Zaskar ranges. It passes through Ladakh and Baltistan. It cuts across the Ladakh range and forms a spectacular gorge near Gilgit.

The river enters Pakistan near Chilas in the Dardistan region. It finally comes out of the hills near Attock. From there it flows southward across the plains.

7. Which tributaries does the Indus collect on the way?

NCERT lists many Himalayan tributaries of the Indus. They are the Shyok, the Gilgit, the Zaskar, the Hunza, the Nubra, the Shigar, the Gasting and the Dras.

Near Attock the Indus receives the Kabul river on its right bank. The other important right-bank tributaries are the Khurram, the Tochi, the Gomal, the Viboa and the Sangar. All of them rise in the Sulaiman ranges.

So the Indus has many direct tributaries besides the five Punjab rivers. That matters later, when we look at the exam trap.

8. Where does the Nubra rise, and does it join the Indus directly?

The Nubra is fed by meltwater from the Siachen Glacier. Siachen is the second-longest glacier outside the polar regions. It is also the site of the world’s highest-altitude military standoff since 1984.

The Nubra flows through the Nubra valley in Ladakh. It then joins the Shyok river near Diskit. The Shyok is itself a tributary of the Indus. So the Nubra reaches the Indus through the Shyok, not directly.

Water that starts on a disputed Karakoram glacier therefore flows through the Nubra, the Shyok and the Indus. It ends in the Arabian Sea.

9. Which glacier feeds which river?

Exams like to pair glaciers with rivers. Five pairings often appear together.

• Bandarpunch and the Yamuna: Yamunotri, the source of the Yamuna, lies on a flank of Bandarpoonch. The glacier feeds the Yamuna.
• Bara Shigri and the Chandra: the glacier feeds the Chandra river in Himachal Pradesh. The Chandra and the Bhaga join to form the Chenab.
• Siachen and the Nubra: the Siachen Glacier feeds the Nubra.
• Milam and the Gori Ganga: the Gori Ganga comes from the Milam Glacier system, not from the Mandakini.
• Zemu and the Teesta: the Zemu Glacier near Kanchenjunga is a source of the Teesta, not the Manas.

So the pairs that match are Bandarpunch with Yamuna, Bara Shigri with Chenab, and Siachen with Nubra.

This is the heart of the topic. Learn each river’s start, then learn the order in which they merge.

10. Which five rivers make the Punjab system, and what is the Panjnad?

Five major rivers cross Punjab: the Jhelum, Chenab, Ravi, Beas and Sutlej. NCERT says the Panjnad is the name given to these five rivers of Punjab.

The Indus receives the Panjnad a little above Mithankot. Britannica says the Panjnad is formed just below Uch by successive junctions of the five rivers. It flows about 71 km southwest to meet the Indus near Mithankot.

11. Where does the Jhelum rise, and where does it end?

The Jhelum rises from a spring at Verinag. The spring lies at the foot of the Pir Panjal, in the south-eastern part of the valley of Kashmir.

It flows through Srinagar and the Wular lake. It then enters Pakistan through a deep, narrow gorge. It joins the Chenab near Jhang in Pakistan.

12. How is the Chenab formed?

The Chenab is formed by two streams, the Chandra and the Bhaga. They join at Tandi, near Keylong in Himachal Pradesh. So it is also known as the Chandrabhaga.

NCERT calls the Chenab the largest tributary of the Indus. The river flows for 1,180 km before entering Pakistan.

13. Where do the Ravi and the Beas rise, and whom do they join?

The Ravi rises west of the Rohtang pass in the Kullu hills of Himachal Pradesh. It flows through the Chamba valley. Before entering Pakistan, it joins the Chenab near Sarai Sidhu.

The Beas starts at Beas Kund near the Rohtang Pass, at about 4,000 metres. It flows through the Kullu valley and forms gorges at Kati and Largi. It enters the Punjab plains and meets the Satluj near Harike.

14. What is special about the Satluj?

The Satluj rises in Raksas tal near Mansarovar, at 4,555 metres in Tibet. There it is known as Langchen Khambab. It flows almost parallel to the Indus for about 400 km before entering India.

It passes through the Shipki La and comes out of a gorge at Rupar. NCERT calls it an antecedent river. It feeds the canal system of the Bhakra Nangal project.

Britannica calls the Sutlej the longest of the five Punjab tributaries of the Indus. NCERT calls the Chenab the largest. So “longest” points to the Sutlej, and “largest” points to the Chenab.

15. In what order do the five rivers merge?

Follow the water from east to west, step by step.

1. The Beas joins the Satluj near Harike. 2. The Jhelum joins the Chenab near Jhang. 3. The Ravi joins the Chenab near Sarai Sidhu. 4. The Satluj, now carrying the Beas, joins the Chenab west of Bahawalpur. 5. The joined stream is the Panjnad, which meets the Indus near Mithankot.

So the Jhelum and the Ravi go into the Chenab, and the Beas goes into the Satluj. Then the Satluj and the Chenab join to form the Panjnad.

16. Which dams stand on the Chenab?

Two big hydropower stations stand on the Chenab in Jammu and Kashmir: Salal and Baglihar.

• Salal: near Reasi, run by NHPC. It has a 113 metre concrete dam and a 118 metre rock-fill dam.
• Baglihar: near Ramban, a 143 metre concrete gravity dam built by the Jammu and Kashmir State Power Development Corporation.

So Baglihar is taller than Salal’s concrete dam. The operators are the other way round from what a careless guess suggests.

The Indus system is shared by India and Pakistan. A 1960 treaty decides who may use which river. In 2025 India placed it in abeyance.

17. What did the Indus Waters Treaty of 1960 decide?

The treaty was signed on 19 September 1960 and took effect from 1 April 1960. India and Pakistan exchanged the instruments of ratification on 12 January 1961. The Indus system has three Eastern Rivers and three Western Rivers.

• Eastern Rivers: the Ravi, Beas and Sutlej. India may use them without restriction.
• Western Rivers: the Indus, Jhelum and Chenab. Pakistan gets them, except for limited uses allowed to India.

The Eastern Rivers carry about 33 million acre feet. The Western Rivers carry about 135 million acre feet.

18. What may India still do on the Western Rivers?

India must let the Western Rivers flow, except for four uses. They are domestic use, non-consumptive use, specified agricultural use and specified hydroelectric power.

Annexure E of the treaty lets India build limited storage on the Western Rivers, about 3.6 million acre feet in all. PIB adds that India may build run-of-the-river hydro projects there, within the treaty’s design rules.

19. How does India use the Eastern Rivers?

India built storage works on the Eastern Rivers. The Bhakra Dam stands on the Satluj. The Pong and Pandoh dams stand on the Beas. The Thein, or Ranjitsagar, dam stands on the Ravi.

The Satluj matters most for Punjab. NCERT says it feeds the canal system of the Bhakra Nangal project. The Bhakra reservoir is called Govind Sagar.

20. What did India decide on 23 April 2025?

On 22 April 2025 a terror attack struck Pahalgam in Jammu and Kashmir. A PIB note puts the toll at 26 deaths.

The treaty was then about 65 years old. The Cabinet Committee on Security met the next day, 23 April 2025. It decided that the Indus Waters Treaty of 1960 would be held in abeyance with immediate effect. The decision stays until Pakistan credibly and irrevocably abjures its support for cross-border terrorism.

21. Why does the abeyance matter for the rivers?

The government’s own note says Pakistan depends heavily on the Indus system. It puts the share at 80% of Pakistan’s 16 million hectares of farmland, and 93% of its water use.

The note says the system supports 237 million people. It also says the Mangla and Tarbela dams hold only about 14.4 million acre feet of live storage. These are the Government of India’s figures, so quote them as such.

Two recent papers asked about the Indus. Both tested the same habit: naming a river without tracing the order of the merges.

22. Which Punjab river joins the Indus directly? The exam trap

Many students assume any of the five names could answer “which tributary joins the Indus”. The trap is the order of the merges.

The Jhelum and the Ravi join the Chenab. The Beas joins the Satluj. The Satluj and the Chenab then join, and the Panjnad carries all five to the Indus.

UPSC 2021 asked this question, and its key is the Sutlej. NCERT says the five rivers reach the Indus as the Panjnad. If a question gives the four rivers and asks for the one that joins the Indus directly, choose the Sutlej. If it asks about the final stream, write Panjnad.

23. What did CDS 2023 and UPSC 2021 ask?

This topic has produced real exam questions built around two different traps.

CDS I 2023 asked how far the Indus river basin extends. The correct answer covers Ladakh, Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana and Rajasthan. That is further east and south than many expect. See this question on the full CDS I 2023 GK paper.

UPSC CSP 2021 tested which river joins the Indus directly. The key is the Sutlej, since the Jhelum and Ravi join the Chenab, and the Chenab then joins the Sutlej. See this question on the full 2021 paper.

24. Which of these is NOT a tributary of the Indus?

A common question lists Beas, Ravi, Chenab and Tawi. The answer is the Tawi.

NCERT names the Jhelum, Chenab, Ravi, Beas and Satluj among the rivers of the Indus system. The Tawi is not in that list. It is a tributary of the Chenab and joins the Chenab in Pakistan.