Its called arbitrage trading. In this regard, it may not be as easy to make money as it sounds. Bitcoin maybe a grey area in India, but I am pretty sure there are strict regulations when it comes to selling INR. Check for applicable FEMA regulations if you intend to do this. My guess is, smaller amounts might pass under the radar but anything substantial would definitely invite trouble.
i dont think that there will be an issue dealing with bitcoin in india and since there are no rules and regulations regarding bitcoin i dont think we will get into trouble dealing with it as long as you dont do anything illegal and if you are within the law it is just fine