That doesn't sound off. Positions in Webmaster Tools are an estimate of where you appear in the SERPs for a given term due to regular changes made to the algorithm as well as normal SERP flux and volatility. Position 20.4 would mean that you're more or less at the bottom of Page 2 or top of page 3 for that search term. And if you have international targeting set to your locale or your site only services people in that region (plus being a .IN site), among other things, likely affects your rankings outside of your region. Which would be why you show up bottom of page 2 when searching in India but then don't appear when doing searches from other places.
As for how to improve this? Well that depends on what your core search terms are, what your site is about, what products/services/information it offers, what locations it is geared towards, quality of content, user experience, how well optimized your on and off-page factors are, your link building efforts, etc. etc.