Zebpay and Unocoin seems to be the most liquid exchanges existing in India according to my knowledge. Zebpay has an advantage of better rates when compare to Unocoin and the fees of the Unocoin is also the highest due to which there may be little less interest of people .
Though there are new exchanges which has recently come up in India but not sure how their volume and their authenticity.
Huh? Zebpay is fast and quite flexible.there verification process is also fast but there buy sell range rates are quite high.where as coinsecure lack speed but their rates are best in the country for buying and selling.it doesn't matter if you are paying high fees at time of exchange or paying afterward.