Yes, the civilization of South Asia started in the indus river basin. There is a conflict about who started it. According to a theory known as a theory of Aryan Invasion, the civilization in the indus valley was purely darkskinned, dravidian and was contemporary to Egypt and Mesopotamia and in fact much more advanced. They were not hindus but they worshipped Shiva. In about 1800 to 1500 BC, these people known as Aryans, fairskinned, from the area where present day black sea is, came to northern India through the Khyber pass in the Hindukush mountain. They gradually became larger in number, they were less civilized than the dravidians but were very warrior like and advanced in literature and already domesticated horses and cows. Later they mixed with (or defeated in some cases) these dravidians but dravidians not accepting the Aryan supremacy started moving southward. Which is why, you don't find any verses dedicated to lord shiva in vedas, which was already completed at this time. They were the first people to migrate everywhere around the south asia.