If you mean what changed in recent times - imperial rule. It has been only 60 years since India has been independent.
India was made up of numerous warring states, until one massive war that turned them into a possession of Britain. I'm not aware of how their economic situation changed after that, but if Africa is any indicator... http://unqualified-reservations.blogspot.com/2007/08/country...
Many people say that far greater damage was wrought by the many Muslim emperors and invasions.
By the time the British came, Indian Science was over.