Which river basin in India is shared by more than ten states and union territories, making it the most extensive drainage system in the country?

Introduction / Context:
River basins play a crucial role in India water resources, agriculture and interstate relations. Some river basins are confined to only a few states, while others stretch across a large part of the country. This question asks which river basin is shared by more than ten states and union territories, highlighting the most extensive drainage system in India.

Given Data / Assumptions:

• We are comparing major river basins in India: Ganges, Indus, Brahmaputra, Damodar and Godavari. • The focus is on how many states and union territories each basin covers. • The answer should be the basin that involves more than ten administrative units.

Concept / Approach:
The Ganges river basin is the largest in India in terms of human population and number of states covered. It stretches from the Himalayan region through the northern plains and extends into eastern India, bringing in contributions from many tributaries such as Yamuna, Ghaghara, Gandak, Kosi and Son. As a result, it involves a very large number of states and union territories. Other basins like the Indus and Brahmaputra are also large, but they do not involve as many Indian states as the Ganges basin does. Damodar is a much smaller basin, and Godavari, although extensive in peninsular India, still covers fewer states compared to the Ganges basin.

Step-by-Step Solution:
Step 1: List the major regions drained by the Ganges basin: Uttarakhand, Uttar Pradesh, Himachal Pradesh parts, Haryana parts, Delhi, Rajasthan parts, Madhya Pradesh parts, Bihar, Jharkhand, Chhattisgarh parts and West Bengal. Step 2: Count that this extended basin influences more than ten states and union territories when you include areas such as Delhi as a separate unit. Step 3: Compare with the Indus basin, which in India mainly covers parts of Jammu and Kashmir region, Himachal Pradesh, Punjab, Haryana and Rajasthan, involving fewer units. Step 4: The Brahmaputra basin mainly lies in Arunachal Pradesh, Assam and some neighbouring areas in the north east, again fewer than the Ganges basin. Step 5: Damodar basin is restricted largely to parts of Jharkhand and West Bengal, and the Godavari basin spans several central and southern states but still fewer than the large number associated with the Ganges basin. Therefore, the Ganges river basin must be the correct answer.

Verification / Alternative check:
Many exam oriented summaries explicitly state that the Ganges basin is shared by the maximum number of states and union territories in India, often more than ten. They also highlight that it supports the largest concentration of India population. In contrast, other basins are described as covering fewer states. This repeated comparison in standard references confirms that the Ganges river basin is the one shared by more than ten states and union territories.

Why Other Options Are Wrong:
Indus river basin: Large in overall size but a major part lies outside India, and within India it primarily covers only a limited set of states in the north and northwest. Brahmaputra river basin: Concentrated mostly in Arunachal Pradesh and Assam within India, not across more than ten states. Damodar river basin: A relatively small basin mainly in Jharkhand and West Bengal. Godavari river basin: Extensive in central and southern India but still covers fewer administrative units than the Ganges basin.

Common Pitfalls:
Students may overestimate the coverage of the Indus or Brahmaputra basins because of their large discharge and long courses, forgetting that much of these systems lie outside India boundaries. Another trap is to focus only on basin area and not on the number of states involved. To answer correctly, you must consider how many different Indian states and union territories each basin touches, and the Ganges basin clearly dominates on this count.

Final Answer:
The river basin shared by more than ten states and union territories in India is the Ganges river basin.