if there was an easy way to purchase bitcoin at lower rates in India the price wouldn't have been this high in first place. it is high because there is no way so the demand is always there at that higher price to purchase.
the only ways are hard ways of trying to give fiat to someone outside of your country so they can buy bitcoin with it at lower rate and you sell it inside country at higher rates and share the profit. you have to find the way to transfer that fiat out though which is not going to be easy.
you can also ask your fellow Indians on the forum here:
https://bitcointalk.org/index.php?board=89.0they may know more than me.