There was a Dravida Civilization in the South before or started with Manu in the south of Vindhyas,
The tribes of Dravidas were left behind by Manu when he left for Ayodhya,
Sage Vasista stayed in the South,
Later when Viswamitra banished his sons to the south, Dravida civilization was in existence during the Ramayana period,
Dravidians were called as Dasyus because of their way of Life was different from Sanatana Dharam though they followed the Sanatana Dharma.
These Dravidian tribes included the ancestors of Greeks, other European tribes, Chinese and Huns.