Should I Open a Pizza Franchise Abroad?
If, as you suggest, there are no pizza franchises in Mumbai, then that might be a warning sign that this product won't work well in that area. In the alternative, it might mean that the market is wide open and the opportunity is very strong. There is no way to know the answer for sure until you do some more research.
Your best option, at least initially, is to contact the major pizza franchise companies (Pizza Hut and Domino's, among others) directly to ask about opportunities with them in Mumbai. I'm sure they have done quite a bit of research into the idea of opening units in your area. Inquire about what this research has determined in terms of whether or not opening a franchise there would be a good idea.
Related: A Pizza Franchisee Explains the Secrets Behind His Success
Related: How to Research a Franchise
Related: International Business Opportunities