How to come sub continent

The Scientists said that '' About 170 millions years ago hindustan was a small insland which was came to asia floated on the sea and attached with Asia. That is why it is suppose that this insland was broke from Africa and floating on the sea and at last reached at Asia and attached with it. Then slowly its surface were drying and this insland was slowly,slowly made bigger and bigger and then Sindh valley came into being about 31-2 or 4 millions. Many mountains came into being due to many climate changes. Such as humalia and himdukush etc.