Hi, I'm currently I'n India on a multiple entry six month visa. I wish to go to Nepal for a few weeks and then enter back into India for the rest of my trip. I have been told that although my visa says multiple entry I would still need to wait 180 days before entering back into India.
Is this true? Any advice?
Most likely you won't be able to return to india in after a few weeks in nepal. Last year this period was two months. Maybe the indian government extended it to half a year?
Reason why they don't allow tourist back within this time because they want to cut off their neighbouring countries from tourism - as they know that india serves as a transit route to these countries. They introduced that after in Nepal the communist government took over power in late 2009. They can also penalize other neighbouring countries as well, like Sri Lanka.
Yes be careful you will have to wait a full 2 months. I know of lots of travellers who couldn't get back in!
To get back in you have to go to the Indian embassy/consulate in kathmandu. There, you can get a re-entry stamp in your passport that will let you go back into India. As I recall it should cost about $10 USD. I think they can process this the same day. I.e. you will go in the morning and drop off your passport, and they will return it to you at the end of the day.
I did this about a year ago, so I assume the process is the same. I met a number of travelers at the embassy who needed to get the same stamp after trying to cross into India and being denied.