baed on my experience in a similar situation, this is the document you want: http://www.gaz.zh.ch/dam/justiz_inne...f/Indien_1.pdf
that's what the zivilstandsamt in Zurich will use to decide what documents you need. but you should ring them in any case to get confirmation, they speak English.
what they seem to want:
- birth certificate issued less than 6 months ago
- some kind of proof of marital status, probably they will want an affidavit of bachelorhood
this has to be apostilled, which in india means State and then MEA, may be best to get an intermediary to do this for you
if you are not traveling back to india to organise this the embassy can probably do the affidavit, or you could try to persuade the zivilstandsamt to accept a Swiss affidavit (i tried this and gave up because i could not find anyone there who knew what an affidavit was)
once you have this stuff they will send it to india to be authenticated (you may have to add copies of school certificates etc.). for this you will pay 900.- deposit, in our case (all papers from mumbai) we got 400.- or so back.
it takes 3 weeks for documents to get there, about 2 months for the guys in india to check them, 3 weeks for the results to get back and then another week or two for processing here (after which you can't get married for another 2 weeks), so take this into account for wedding planning.
might be able to accelerate this by having the embassy scan some stuff in and send by email to the zurich guys to skip the 3 week delay sending things back, but when i tried they messed it up.
generally the zivilstandsamt are quite helpful even by phone, so dont hesitate to talk to them before and during the process.