You need to broaden your horizon, and think about the bigger picture. Chinese automobile plant in India will not be Indian market specific, it can cater to other south asian, african, middle east markets too.
Well, it will be India specific. Chinese don't need Indian labor to export to S.asia. They have SL & if stable environment allows , BD for that. U are again sounding like India is the center point concerning investment in S.aisa. India doesn't own S.asia.
And rise of labor cost in chian is far cry from now. They still have the economically underdeveloped W.china to supply them labor.