You'll have to buy it off Zebpay/Coinsecure to initially beging with or you can even try cex.io.
For trading start with Poloniex, and then go to Bittrex.
We have Koinex and Bitpay coming up for buying/selling alt coins. Check them out.
Is everything fine with Poloniex, because in between somewhere I was reading some issues with people regarding this exchange. Also doe they have an option of INR deposit with Koinex and Bitpay directly or wee need to first buy btc and then transfer to their exchange and then get converted to altcoin?