UPSC Prelims 2026Question 25Geography

Identify the river of the Indian sub-continent on the basis of the folloswing information:
1. It has an antecedent drainage system.
2. It flows through three countries.
3. It originates in the Tibetan Plateau and is an important river for irrigation.
4. It does not form distributaries.
Select the answer from the following:

Options

(a)Brahmaputra
(b)Indus
(c)Sutlej
(d)Teesta

Correct answer: c

Decision rule

In river-clue sets the negative clue discriminates: 'forms no distributaries' means a tributary, not a trunk river building a delta.

Explanation

Correct Answer

(c) Sutlej

Explanation of the Correct Answer

The river described is the Sutlej.

Statement 1: It has an antecedent drainage system
The Sutlej is an antecedent Himalayan river. It existed before the final uplift of the Himalayas and cut deep gorges through the mountains.
Statement 2: It flows through three countries
The Sutlej flows through:
- Tibet / China
- India
- Pakistan
Statement 3: It originates in the Tibetan Plateau and is an important river for irrigation
The Sutlej originates near Lake Rakshastal / Manasarovar region in Tibet. It is very important for irrigation, especially through projects such as:
- Bhakra-Nangal Project
- Indira Gandhi Canal system
- canal irrigation in Punjab, Haryana and Rajasthan
Statement 4: It does not form distributaries
The Sutlej is a tributary of the Indus system and does not form a major distributary network of its own.

Therefore, the correct answer is (c) Sutlej.

Why Other Options Are Incorrect

Option	Verdict	Explanation
(a) Brahmaputra	Incorrect	It is antecedent and flows through Tibet/China, India and Bangladesh, but it forms distributaries as part of the Ganga-Brahmaputra delta system.
(b) Indus	Incorrect in this question’s intended framing	Although the Indus is antecedent, originates near Tibet and is important for irrigation, the specific combination of clues, especially “does not form distributaries”, points to the Sutlej as a tributary river.
(c) Sutlej	Correct	It originates in Tibet, flows through China/Tibet, India and Pakistan, is antecedent, important for irrigation, and does not form distributaries.
(d) Teesta	Incorrect	Teesta does not flow through three countries and does not originate in the Tibetan Plateau in the same way.

Relevant Supplementary Information

Sutlej River: Key Facts

Aspect	Details
Ancient name	Shatudri / Shutudri
Source	Near Lake Rakshastal, close to Manasarovar region, Tibet
Countries / regions	Tibet/China, India, Pakistan
Indian states/UTs	Himachal Pradesh, Punjab
Drainage type	Antecedent drainage
River system	Indus river system
Nature	Tributary of the Indus system
Major project	Bhakra-Nangal Project
Irrigation importance	Punjab, Haryana, Rajasthan canal irrigation
Distributaries	Does not form a major distributary system

Comparison of Rivers in the Options

River	Origin	Countries Covered	Antecedent?	Distributary Feature	Verdict
Brahmaputra	Tibet	China/Tibet, India, Bangladesh	Yes	Forms major distributary-delta system with Ganga	Incorrect
Indus	Tibetan region near Kailash-Manasarovar	China/Tibet, India, Pakistan	Yes	Has a deltaic outlet, but not the intended answer here	Incorrect
Sutlej	Tibet near Rakshastal	China/Tibet, India, Pakistan	Yes	Does not form distributaries of its own	Correct
Teesta	Sikkim Himalaya	India, Bangladesh	No, not in the same intended sense	Tributary of Brahmaputra system	Incorrect

Antecedent Himalayan Rivers

River	River System	Why It Is Antecedent
Indus	Indus system	Cuts deep gorges across the Himalayas
Sutlej	Indus system	Maintains course across the Himalayan uplift
Brahmaputra	Brahmaputra system	Cuts through the Himalayas after flowing eastward in Tibet
Kali / Sharda	Ganga system	Himalayan antecedent drainage features
Tista / Teesta	Brahmaputra system	Sometimes discussed as Himalayan river, but not the best fit here

Key Takeaways from the Tables

Sutlej = Shatudri / Shutudri in ancient texts.
It originates in Tibet near Rakshastal / Manasarovar region.
It flows through Tibet/China, India and Pakistan.
It is an antecedent river of the Indus system.
It is extremely important for irrigation through the Bhakra-Nangal system and canal networks.
Unlike the Brahmaputra, it does not form a distributary system.

Point	Explanation
Antecedent drainage is common among Himalayan rivers	Indus, Sutlej and Brahmaputra are classic examples.
Distributary clue is decisive here	Brahmaputra forms a deltaic distributary system; Sutlej does not.
Sutlej is a tributary, not a delta-forming trunk river	It joins the Indus system and does not create distributaries of its own.
Drainage pattern questions need classification logic	Identify source, flow direction, mouth, drainage pattern and river system.
Himalayan rivers are not all alike	Some form deltas, some join larger systems, and some are mainly irrigation/hydropower rivers.
Sutlej is important for irrigation	Especially through Bhakra-Nangal, canal systems and the Indus Waters Treaty framework.

Point	Explanation
Sutlej originates in Tibet	It rises near Rakshastal, close to the Manasarovar region.
Sutlej flows through three countries	China/Tibet, India and Pakistan.
Sutlej is antecedent	It cuts across the Himalayas and existed before the present relief developed.
Sutlej is important for irrigation	Bhakra-Nangal and canal systems support Punjab, Haryana and Rajasthan.
Sutlej does not form distributaries	It is a tributary of the Indus system and does not build a distributary network of its own.
Sutlej = Shatudri / Shutudri	This is an important ancient-modern river name pair.
Under Indus Waters Treaty, Sutlej is an eastern river	It is allocated mainly for India’s use.

Context and Current Relevance

The Sutlej is crucial for irrigation and hydropower in north-western India.
It supports major projects such as Bhakra-Nangal, one of India’s landmark multipurpose river valley projects.
It is also part of the Indus Waters Treaty framework, under which Sutlej is one of the eastern rivers allocated for India’s use.

Table: Classification of Rivers Based on Drainage Pattern / Origin / Course

Basis of Classification	Type	Meaning	Examples in Indian Subcontinent
Based on age of river course	Antecedent drainage	River existed before the uplift of the mountains and continued cutting through them	Indus, Sutlej, Brahmaputra, Arun
	Consequent drainage	River flows according to the original slope of the land	Godavari, Krishna, Kaveri, Mahanadi
	Subsequent drainage	River develops later along zones of weaker rocks	Chambal, Betwa, Ken, Son
	Superimposed drainage	River cuts across underlying rock structures because its course was imposed from an earlier surface	Damodar, Subarnarekha, Chambal in some interpretations
Based on source region	Himalayan rivers	Originate in Himalayas / Trans-Himalayan region; mostly perennial	Indus, Ganga, Brahmaputra, Sutlej
	Peninsular rivers	Originate in Peninsular plateau; mostly rain-fed	Godavari, Krishna, Kaveri, Narmada, Tapi
Based on duration of flow	Perennial rivers	Flow throughout the year due to snowmelt, glaciers and rainfall	Ganga, Yamuna, Indus, Brahmaputra
	Seasonal rivers	Flow mainly during rainy season	Luni, Banas, Peninsular streams
Based on direction of flow	East-flowing rivers	Flow into Bay of Bengal	Ganga, Brahmaputra, Mahanadi, Godavari, Krishna, Kaveri
	West-flowing rivers	Flow into Arabian Sea	Indus, Narmada, Tapi, Sabarmati, Mahi, Luni
Based on mouth	Delta-forming rivers	Deposit sediments and form distributaries near the mouth	Ganga-Brahmaputra, Mahanadi, Godavari, Krishna, Kaveri
	Estuary-forming rivers	Enter sea through a narrow mouth without large distributary network	Narmada, Tapi, Sabarmati, Mahi
Based on basin outlet	Exorheic drainage	Rivers drain into the sea or ocean	Ganga, Indus, Brahmaputra, Godavari
	Endorheic / inland drainage	Rivers drain into inland basins, lakes or disappear in desert	Luni, Ghaggar in its present seasonal form

Table: Important Drainage Patterns

Drainage Pattern	Meaning	Indian Examples / Regions
Dendritic	Tree-like branching pattern; develops where rocks are uniform	Northern plains, Ganga basin, Godavari basin
Trellis	Main streams and tributaries meet at near right angles; common in folded terrain	Himalayan foothills, Singhbhum region
Radial	Rivers flow outward from a central highland	Amarkantak plateau: Narmada, Son, Mahanadi origins
Centripetal	Rivers flow inward into a basin or lake	Sambhar Lake region, inland drainage of Rajasthan
Rectangular	Rivers follow joints and faults, making sharp bends	Vindhyan region and fractured rock areas
Parallel	Rivers flow almost parallel due to steep slope	Western Ghats west-flowing streams
Annular	Ring-like drainage around domes or basins	Rare; found in some structural basins

Table: Major Indian Rivers by Mouth Type

River	Flows Into	Mouth Type	Reason / Feature
Ganga-Brahmaputra	Bay of Bengal	Delta	Huge sediment load and low-gradient coast
Mahanadi	Bay of Bengal	Delta	Deposits sediments on eastern coast
Godavari	Bay of Bengal	Delta	Large east-flowing peninsular river
Krishna	Bay of Bengal	Delta	Forms delta in Andhra Pradesh
Kaveri	Bay of Bengal	Delta	Fertile delta in Tamil Nadu
Indus	Arabian Sea	Delta	Forms Indus delta, though distributary development is less relevant for the Sutlej question
Narmada	Arabian Sea	Estuary	Flows through rift valley; steep gradient near mouth
Tapi	Arabian Sea	Estuary	Rift-valley west-flowing river
Sabarmati	Arabian Sea	Estuary	Smaller sediment load and west coast conditions
Mahi	Arabian Sea	Estuary	Enters Gulf of Khambhat

Table: Himalayan vs Peninsular Rivers

Feature	Himalayan Rivers	Peninsular Rivers
Age	Geologically younger in present form but often include antecedent rivers	Older and more stable courses
Source	Glaciers, snowfields, high mountains	Plateaus and hills
Flow	Mostly perennial	Mostly seasonal, though large rivers flow year-round
Valleys	Deep gorges in mountains, wide plains downstream	Broad, shallow valleys; some rift valleys
Sediment load	High	Comparatively lower
Drainage pattern	Antecedent, dendritic, trellis etc.	Dendritic, radial, rectangular, parallel
Flood tendency	High in plains due to snowmelt and monsoon	More monsoon-dependent
Examples	Indus, Ganga, Brahmaputra, Sutlej	Godavari, Krishna, Kaveri, Narmada, Tapi

Table: Rivers in the Question Classified Properly

River	Source Region	Countries / Regions	Drainage Type	Mouth / Final System	Key Reason for Rejection or Selection
Brahmaputra	Tibet	China/Tibet, India, Bangladesh	Antecedent	Forms distributary-rich Ganga-Brahmaputra delta	Rejected because it forms distributaries
Indus	Tibetan region near Kailash-Manasarovar	China/Tibet, India, Pakistan	Antecedent	Arabian Sea through Indus delta	Similar clues, but not intended because it has a deltaic outlet
Sutlej	Tibet near Rakshastal	China/Tibet, India, Pakistan	Antecedent	Joins Chenab; part of Indus system	Correct: antecedent, transnational, irrigation-important, no distributaries of its own
Teesta	Eastern Himalaya / Sikkim region	India, Bangladesh	Himalayan river	Joins Brahmaputra system	Rejected because it does not flow through three countries and does not fit Tibetan Plateau clue

Table: Sutlej River at a Glance

Aspect	Details
River	Sutlej / Satluj
Ancient name	Shatudri / Shutudri
Source	Near Lake Rakshastal, close to Manasarovar region in Tibet
Origin region	Tibetan Plateau
Countries through which it flows	China/Tibet, India, Pakistan
Indian states	Himachal Pradesh, Punjab
River system	Indus river system
Drainage type	Antecedent drainage
Major project	Bhakra-Nangal Project
Major dam	Bhakra Dam
Irrigation importance	Punjab, Haryana and Rajasthan
Distributaries	Does not form a major distributary system
Indus Waters Treaty status	Eastern river allocated to India

Table: Important Himalayan Antecedent Rivers

River	River System	Origin / Region	Important Feature
Indus	Indus system	Near Kailash-Manasarovar region	Cuts deep gorges through Himalayas
Sutlej	Indus system	Near Rakshastal, Tibet	Antecedent river; important for irrigation and hydropower
Brahmaputra	Brahmaputra system	Tibet	Flows as Yarlung Tsangpo in Tibet; cuts through Himalayas at Namcha Barwa
Kali / Sharda	Ganga system	Greater Himalayas	Forms part of India-Nepal boundary
Arun	Kosi system	Tibet / Nepal Himalayas	Major antecedent tributary of Kosi
Karnali / Ghaghara	Ganga system	Tibetan-Himalayan region	Important trans-Himalayan drainage
Teesta	Brahmaputra system	Eastern Himalayas	Himalayan river, but not the best answer for the question

Table: Sutlej and Major Irrigation / Hydropower Projects

Project / Structure	State / Region	River / System	Importance
Bhakra Dam	Himachal Pradesh	Sutlej	Major multipurpose dam for irrigation, hydropower and flood control
Nangal Dam	Punjab	Sutlej	Regulates water from Bhakra system
Bhakra-Nangal Project	Himachal Pradesh / Punjab	Sutlej	Supports irrigation in Punjab, Haryana and Rajasthan
Indira Gandhi Canal	Rajasthan	Uses waters linked to Sutlej-Beas system	Provides irrigation to arid western Rajasthan
Harike Barrage	Punjab	Confluence zone of Beas and Sutlej	Diverts water into canals including Rajasthan feeder systems
Koldam Hydroelectric Project	Himachal Pradesh	Sutlej	Hydropower generation
Nathpa Jhakri Project	Himachal Pradesh	Sutlej	One of India’s major hydropower projects

Table: Ancient and Modern Names of Rivers Related to the Indus System

Ancient Name	Modern Name	River System
Sindhu	Indus	Indus system
Vitasta	Jhelum	Indus system
Asikni	Chenab	Indus system
Parushni / Iravati	Ravi	Indus system
Vipasha	Beas	Indus system
Shatudri / Shutudri	Sutlej	Indus system
Kubha	Kabul	Indus system
Suvastu	Swat	Indus system
Krumu	Kurram	Indus system
Gomati / Gomal	Gomal	Indus system

Table: Indus Waters Treaty and the Sutlej

Category	Rivers	Allocation under Indus Waters Treaty, 1960
Eastern Rivers	Ravi, Beas, Sutlej	Allocated mainly for India’s use
Western Rivers	Indus, Jhelum, Chenab	Allocated mainly for Pakistan’s use, with limited use permitted to India
Sutlej’s status	Eastern river	India has major utilization rights
Importance for India	Irrigation, hydropower, canal systems	Crucial for Punjab, Haryana and Rajasthan
Importance for Pakistan historically	Part of Indus basin flows	Treaty created replacement works for Pakistan after allocation of eastern rivers to India

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