Many ways, my brother. Flood the country with drugs and start offering discounts to converted Hindus.
Offer positions of power for conversion.
Run a literal drug cartel focused on Hindu conversions.
Hell, refuse sale of drugs once someone is addicted unless he/she converts.
I have seen very well with my own two eyes what drugs do to an otherwise committed man.
I guarantee, everyone is breakable, especially once their habit becomes chronic.
RAW is fully capable of doing this, but they probably won't due to "morality".
I can't even make sense of why we have such an organisation if it isn't willing to get down and dirty in the mud.
Also, I understand it's unsavory and a very wild idea (mixing religion with drugs) but it's a workable concept. Targeting school-going kids and University students is the way to do it, mainly because they're the ones whose views have neither solidified nor can they support this habit indefinitely and will definitely break easy.