Explanations:The cities of Delhi, Islamabad, and Dhaka share a common geographical feature that supports their dense populations: their proximity to major rivers. Rivers have historically played a crucial role in the development and sustenance of urban areas. The presence of a major river near a city provides several advantages that contribute to its ability to support a large population.
Firstly, rivers are a vital source of fresh water, which is essential for drinking, sanitation, and irrigation. This ensures that the population has access to clean water, which is necessary for daily life and agriculture. In the case of Delhi, the Yamuna River provides a significant water supply. Islamabad is near the Ravi River, and Dhaka is near the Buriganga River, both of which are important for the cities' water needs.
Secondly, rivers facilitate transportation and trade. Historically, rivers have been used as natural highways for the movement of goods and people. This has allowed cities to develop into important commercial centers, attracting more people and fostering economic growth. The ability to transport goods via river can reduce costs and increase efficiency, which is beneficial for urban development.
Thirdly, rivers can support agriculture, which is crucial for feeding a large urban population. The fertile floodplains near rivers provide excellent conditions for growing crops, which can help sustain the city's food supply. This agricultural productivity can also contribute to the economic stability of the region, further supporting urban growth.
It is important to note that while other factors such as coastal locations, geographical position relative to the Tropic of Cancer, and proximity to mountain ranges can influence urban development, they are not as universally applicable to the cities in question as the presence of a major river. Coastal locations, for example, are not a common feature among Delhi, Islamabad, and Dhaka. Similarly, while the Tropic of Cancer is a geographical boundary, it does not directly influence the ability of a city to support a dense population. The proximity to the Himalaya Mountains is also not a shared feature among these cities, making it an irrelevant factor in this context.
In conclusion, the presence of a major river near a city is a significant factor that supports dense urban populations. This is evident in the case of Delhi, Islamabad, and Dhaka, where the rivers provide essential resources and facilitate economic activities that contribute to the cities' ability to sustain large populations.