The Aryan Invasion ? The Fascist theory is .....?

There are many theories...about the Aryans....in India we are taught that ....a tribe from central Europe or the Balkans arrived here 5000 years ago....and no one knows how the Indus Valley Civilization was destroyed.....according to Hitler the Aryans invaded India at that time....i believe these Aryans were from central and eastern Europe and not from Germany.... and they never invaded India....they intermingled with the Dravidians(the original inhabitants of the Indus Valley)...and therefore there is such a wide range of difference in R1b haplogroup population in India