Orthographic projection of the Indian subcontinent
Map of the Indian subcontinent
Geologically, the Indian subcontinent was first a part of so-called "Greater India", a region of Gondwana that drifted away from East Africa about 160 million years ago, around the Middle Jurassic period. The region experienced high volcanic activity and plate subdivisions, creating Madagascar, Seychelles, Antarctica, Austrolasia and the Indian subcontinent basin. The Indian subcontinent drifted northeastwards, colliding with the Eurasian plate nearly 55 million years ago, towards the end of Paleocene. This geological region largely includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The zone where the Eurasian and Indian subcontinent plates meet remains geologically active, prone to major earthquakes.
Using the more expansive definition – counting India, Pakistan, Bangladesh, Sri Lanka, Nepal, Bhutan and Maldives as the constituent countries – the Indian subcontinent covers about 4.4 million km2 (1.7 million sq mi), which is 10% of the Asian continent or 3.3% of the world's land surface area. Overall, it accounts for about 45% of Asia's population and over 25% of the world's population, and it is home to a vast array of peoples.
Historical transmission routes of Buddhism from India to Central Asia, East Asia and Southeast Asia
NASA images of the Indian subcontinent during day and night.
The Indian subcontinent is a natural physical landmass in South Asia, geologically the dry-land portion of the Indian Plate, which has been relatively isolated from the rest of Eurasia.
Given the difficulty of passage through the Himalayas, the sociocultural, religious and political interaction of the Indian subcontinent has largely been through the valleys of Afghanistan in its northwest, the valleys of Manipur in its east, and by maritime routes. More difficult but historically important interaction has also occurred through passages pioneered by the Tibetans. These routes and interactions have led to the spread of Buddhism out of the Indian subcontinent into other parts of Asia. And the Islamic expansion arrived into the Indian subcontinent in two ways, through Afghanistan on land and to Indian coast through the maritime routes on the Arabian Sea.
The Hindu Kush, centered on eastern Afghanistan, is the boundary connecting the Indian subcontinent with Central Asia to the northwest, and the Persian Plateau to the west. The socio-religious history of Afghanistan are related to the Turkish-influenced Central Asia and northwestern parts of the Indian subcontinent, now known as Pakistan. Others state Afghanistan being a part of Central Asia is not an accepted practice, and it is "clearly not part of the Indian subcontinent".
The precise definition of an "Indian subcontinent" as opposed to "South Asia" in a geopolitical context is somewhat contested.