you think??? AIT is rubbish.
The inhabitants of IVC/SSC moved to greener pastures in the west due to cataclysmic event (in this case drying up of river Saraswati). Aryans or the so called newcomers came in towards the end of late Happan period- around 1000BC. Unlike Harappans, these newcomers used to live in circular huts, and had inferior wares.
There has been no instance of recorded evidence of new gene being introduced in the Indian gene pool post 3000 B.C. Paper Published in Nature and one more Journal. Aryan Invasion is a lie.