my question is simple can .in domain extension make authority site? or only .com extensions make authority sites?
It is all about the site itself and both the quality(MAINLY), but as well as the quantity of the backlinks pointing to it. The TLD doesn't matter at all... Still I would avoid .in unless the site is really about India.
Sites with a ".whatever" extension will have the potential of ranking as high as a .com site. As abraxas said above, it depends on your content and backlinks mostly. In the past Google supposedly favored .com sites but now, with so many high ranking sites that don't have a .com (ie: ow.ly or even goo.gl) they have to take all extensions into consideration. *BUT* there has been a push with larger sites that started with an extension that wasn't .com (ie: bit.ly) who are now using a .com extension mainly (ie: bitly.com is their primary domain now). That being said, the majority of the world still thinks in a ".com" mindset, so if they need to type in your url for some reason, and they don't remember that it is an .in domain, they'll try .com first. So if your content is amazing and you get lots of shares and backlinks, there is no reason that you cannot fully succeed with a .in name. Especially if the 'in' part fits into a name you want, or really if you're just in India!
In my experience I have had a harder time getting sites ranked with less known extensions. I think it takes more to get a site ranked with the big dogs if you have a crappy extension. I always try to stick with the .coms unless the keywords are absolutely amazing.
I think it may have a effect to some extent but the thing that mostly matters for search engines is the quality and original content with good quality inbound links. By the good quality I mean links from higher authority and higher rank pages.