currently we dont have that provision in Indian Income tax. I will suggest it you do quickly. You can even pay tax on it. There is nothing wrong in it.
Or you can buy or sale in cash as well. Its your choice completely.
Govt has already clarified that if you are selling btc within 3 years of purchase then 30% on the profit will need to be as a short term profit. So you can easily sell on exchanges or to anybody and if you are gaining from the sale then pay 30% on profit and show in your tax filing . Else rest is upto you if you do not wish to do this legal way as suggested by government.