I would suggest you to buy Bitcoin from coinsecure.in because you will get it in lesser price compare to Zebpay and Unocoin.
I highly not recommend buying from Zebpay and Unocoin as they are merchant/dealer who charges you higher price and higher trading charges.They set their own selling and buying price making spread high.
Where in the case of coinsecure it is the only exchange in India where the spread between buy and sell is small. So you can make good amount of profit by quick buying and selling.
There is another exchange koinex.in which is going to be release on 25th August 2017. It will be first cryptocurrency exchange with multiple coins platform to trade . During the initial release you can trade on - Bitcoin,Litecoin, Ethereum and Ripple. After sometime they will also provide platform for ethereum based token.
Do you own research before investing.Farewell.