Nobody is going to sell you at preev rate since all other exchanges are giving preev+10% on selling so why will any one sell to you 10% less?
Also you are a newbie so just see if any is willing to sell will be good.
Any suggestions on buying BTC at international rates via Debit Card, IMPS, PayTM, etc
Technically it is possible at
http://cex.io using your credit card/bank transfer. However, I would avoid it, and rather buy from one of the available IN exchanges.
Those accepting Credit /Debit Card are charging a heavy premium cex.io is selling 1