How did the geography of the Indian subcontinent influence the development of civilization there?
Geography will always influence how people develop economically, culturally, and politically. In present-day Pakistan, the Harappan Civilization developed along the Indus River. The river system, as well as the yearly monsoons, provided plenty of water to support agriculture. The annual flooding of the river left behind fertile soil to plant crops like wheat and barley. The rivers were so vital to the success of Mohenjo-daro and Harappa that when some parts of the system dried up, the civilization went into decline.
Another important aspect of the location of the Harappan civilization was the isolation. The mountains to the west and north acted as a barrier from invasion by outside people. The Arabian Sea to the south and west also had the same effect. The isolation that was set by the geography allowed the cities to focus on infrastructure and technology. There is very little evidence in the archaeological record that the Dravidians of these city-states allocated resources for military purpose. As a result, Mohenjo-daro and Harappa were some of the most developed cities in the world. Geography played an important role in that development.
The most important element of Indian civilization to influence development of civilization was the sub-continent's river system. The earliest civilization, the Dravidian, developed along the Indus River which, like the Nile in Africa, flooded and deposited rich soil carried from upstream which made agriculture possible. Unlike the Nile which was somewhat predictable, the flooding of the Indus was arbitrary and capricious. 'The Harapan society occupied all of present day Pakistan and much of Northern India. Its people were the first to domesticate chickens, and also grew large amounts of cotton, wheat and barley.
There is evidence the Dravidian civilization went into decline because of deforestation as more land was cleared for planting. Unfortunately, their language has not yet been deciphered and must of the remains of their largest cities are underwater; so there is little known about their culture or religion.