It's hard to say as each case and each office is unique. Security clearances will extend the time if you need them. the current strike depending on what office you are applying through can have an effect as well.
not sure with that office, I think your best bet would be looking at other people experiences in the New Delhi thread of asking in there. if they have a spreadsheet that will give you a pretty good idea of how long stuff is taking there.
Edit: Looks like they answered your question in the New Delhi thread, albeit in a rather rude fashion.