Explanation: The Yamuna River is a crucial tributary of the Ganga River and plays a significant role in the geography and hydrology of northern India. The Yamuna originates from the Yamunotri Glacier in the Himalayas and flows through several states, including Uttarakhand, Haryana, and Uttar Pradesh, before merging with the Ganga at Allahabad (Prayagraj).
In the context of Delhi, the Yamuna River is particularly important as it flows through the city, dividing it into two parts: the northern part, which includes the urban areas of New Delhi and Old Delhi, and the southern part, which includes areas like Noida and Gurugram. The river is not only a source of water for the city but also a significant ecological and cultural feature.
The Yamuna is the primary tributary of the Ganga that flows through Delhi, making it the correct answer to the question. Other tributaries of the Ganga, such as the Chambal, Betwa, and Ghaghara, do not flow through Delhi. The Chambal and Betwa are tributaries of the Yamuna itself, and the Ghaghara flows much further north and east of Delhi.
Understanding the river systems and their tributaries is essential for comprehending the geographical layout of the region. The Yamuna's role in the drainage pattern of Delhi and its significance in the Ganga river system make it a key geographical feature that students should be familiar with when studying the geography of Delhi and northern India.