Know-How Exchange : Research/Metrics

Great question to start off the new year !

Prior to specific market research, I would venture there are two potential markets for Mexican food in India:
a) indians who have been exposed to Mexican food when abroad (e.g. working in / traveling to the US, UK,... and of course Mexico)
b) middle to upper indians who want to experience a new cuisine and/or 'show off' their international taste to their friends and neighbours.

The size and accessiblity of these two segment will determine not just your market potential but also your best positioning and pricing strategy. Though my experience is in Turkey, not India, these countries have many similarities, including that the excellent quality of local food implies a low penetration of foreign restaurants. If segment B above is important to you, the Turkish experience shows that any international restaurant needs to start with an upscale and high price image. If you start at the middle-to-low end, it is very tough to compete with the cheap and excellent local food

For instance, the Mongolian barbeque, for which I paid $ 5 in a bare-bone atmosphere in Los Angeles, in Istanbul starts at $35 and is positioned as an 'expensive first date' kind of experience. The taste and quality of the food is the same....
The good news is that it is basically an image game with segment B: you need to spend on atmosphere, but could sell rather low-quality food at a very high price and few people will notice. Chinese restaurants in Istanbul are a good example.

In contrast, if most of your customers are from segment A, this means you need to bring your quality-price positioning closer to that in international markets. Thus, you can sell the fast-food versions of Mexican food at only a small premium over fast-food prices, while you need high quality Mexican food to charge high prices.

If you need numbers, it should be relatively easy to get data on the number of people in each city market that work abroad (segment A). Segment B is a bit tougher to guesstimate; you could look at the clientele of all the other foreign restaurants in the city market.