Why does the search engine rank vary per google domains. So, for example if I am searching for "apartment for rent in hyderabad" in www.google.com, I do get a result from my site on the first page, but when i do the search from www.google.co.in I get the result on the 3 or 4th page. As my site is for India and google automatically uses google.co.in for users from India, my result is on the 4th page. Any inputs?
IPs of your partner sites from other countries, not from India, so Google prefers sites with more "indian" ties. It's my opinion
Well, I think that the local google page display your site according to its placement in the search results in indian, that is why there is a difference. And it depends on the target audience you seek for. But it does not matter really as the difference cannot be such big if you have well established website. Good Luck!