Climate, and the Human Landscape The geographical borders of pre-nation-states or polities are difficult to chart out clearly. Yet it is more often than not that geography shapes political and cultural entities. South Asia forms one such entity, having physiographical markers that define the space both geographically and culturally. 1 This space is bounded by the Balochistan highlands to the west, the Swat valley in the northwest, the Himalayas in the north, the meridional mountain chain of Indochina in the east, and the peninsular region in the south. The peninsular south is surrounded by the Arabian Sea in the west, the Bay of Bengal in the east, and the Indian Ocean in the south. An extensive coastline of 11,104 km in total surrounds the Indian subcontinent (map 1). 2 Three physiographic divisions mark the mainland of the subcontinent: the Himalayas, the Indo-Gangetic Plains, and the peninsula. 3 The Himalayas are young tectonic mountains with various glacial snow formations. Melting glacial deposits form three perennial river systems, the Indus, the Ganga, and the Brahmaputra, with various distributaries and tributaries. These river systems inundate the northern plains and form deposits of fertile alluvial soil. The Indus River system flows into the Arabian Sea, while the Ganga and the Brahmaputra flow into the Bay of Bengal. The alluvial plains are bordered by the Aravali and Vindhya Ranges in the south. The Aravali plateaus are the oldest physiographical formations, and it is here that the Deccan plateau and peninsular India begin. Peninsular India is characterized by smaller zones, such as the lava trap topography with black soil in the western and upper Deccan, 4 granite areas in the eastern region, and red soil in the southern peninsula. 5 There are also pockets of alluvial soil zones in the Narmada, Tapti, Mahanadi, Godavari, Kaveri, and Krishna River valleys. 6