Which of the following rivers originates in India and then flows westward into Pakistan, forming part of the Indus river system?

Introduction / Context:
India and Pakistan share several rivers as part of the Indus river system, and their courses play a major role in agriculture and water sharing treaties. This question focuses on identifying a river that flows from Indian territory into Pakistan. Recognising such transboundary rivers is an important part of political and physical geography of South Asia.

Given Data / Assumptions:
• The question asks about a river that flows from India to Pakistan. • It must be one of the options listed. • Options are Satluj, Ghaghra, Betwa, Tapi and Mahanadi. • We consider the general direction and basin of each river as presented in school geography texts.

Concept / Approach:
Satluj is one of the main tributaries of the Indus river system. It flows through the north western part of India and then enters Pakistan, contributing to the Indus basin. The approach is to recall which of the given rivers belong to the Indus system and cross the India Pakistan boundary.

Step-by-Step Solution:
Step 1: Identify rivers that are part of the Indus basin. Satluj is a well known tributary of the Indus. Step 2: Note that Satluj flows through Himachal Pradesh and Punjab in India and then crosses the international border into Pakistan. Step 3: Ghaghra is a tributary of the Ganga and flows through Nepal and India, not into Pakistan. Step 4: Betwa is a tributary of the Yamuna in central India and remains entirely within India. Step 5: Tapi flows through central India towards the Arabian Sea but does not enter Pakistan. Step 6: Mahanadi is an east flowing river in eastern India and empties into the Bay of Bengal, with no link to Pakistan. Step 7: Therefore, the only river from the list that flows from India to Pakistan is Satluj.

Verification / Alternative check:
Hydrology and river basin maps of the Indus clearly show Satluj entering Pakistan after flowing through Indian Punjab. The Indus Waters Treaty also identifies Satluj as one of the eastern rivers whose waters are largely allocated to India, but its channel continues into Pakistan. Other rivers listed are part of Ganga or peninsular systems and do not cross into Pakistan.

Why Other Options Are Wrong:
Ghaghra: A tributary of Ganga that flows through Nepal and India, not into Pakistan. Betwa: Flows in central India as a tributary of Yamuna and remains entirely within Indian territory. Tapi: A west flowing peninsular river that joins the Arabian Sea near Gujarat, without entering Pakistan. Mahanadi: An east flowing river of eastern India that empties into the Bay of Bengal, far from Pakistan.

Common Pitfalls:
Some learners may confuse all west flowing rivers and assume that any river flowing west must cross into Pakistan, which is not correct in the case of Tapi. Others mix up tributaries of Ganga with those of Indus simply because they are in northern India. A good memory aid is to explicitly link Satluj, Jhelum and Chenab with the Indus system and Pakistan, while keeping Ganga tributaries separate.

Final Answer:
Among the given rivers, the one that flows from India to Pakistan is the Satluj.