I know, right? Most Indians I know are brown caucasians. I feel more related and connected with them than east Asians and Africans because their facial features match mine/ours. I think South Indians may have come from different stock however. They have always had a mixed society.
I did a bit of reading, and the quick info I garnered is that the darker South Indians have DNA similar to Australian aborigines (australoid). And of course, those have mingled over the centuries somewhat.