According to this article, real estate price in Mumbai has gone up by 30% over last 6 month (certainly the clear sign of bubble!). If you are purchase 2 bed room condo in Goregaon, the price is Rs 12 mil ($260K). By putting 15% down and borrow the rest at 9% interest rate, your monthly payment is Rs 90,000 ($2,000) a month (on top of it you pay HOA, insurance and property tax). The rent on equivalent property is Rs 20,000 (gross yield of 2.5%).
Thus, if you are to determine the property value on rental yield, Mumbai real estate is certainly "bubble" territory