What are the major contributions to South Asian culture made by the invading Aryans?

With the Aryan invasion of South Asia, lot has changed, or modified in the way of life of the people in this region. The Aryans managed to merge the culture and beliefs with the Dravidian ones, and thus creating the modern Hindu religion which is essential part of the lives of the people in South Asia. Also, they created the caste system, which led to specialization in work of the people, and even though nowadays it is officially forbidden, in practice, it is still in use. And very important, they created the Indian ethnic identity, with their genetic contribution, were a new ethnicity was formed from two totally different ethnic groups in appearance.