Since when is Windows shared source? Sorry, I am less than informed here.
Since 2001. http://www.microsoft.com/en-us/sharedsource/default.aspx
Ok, so Windows is not opaque, but "largely" opaque. Weasel word! :-) You are given an email address to ask for the source code. Who knows if what they give you is the "backdoors removed" version! Does the Indian government conduct security audits, and do custom OS builds, and checksum files to verify Microsoft is giving them the "real" source code? There are too many ways to do this wrongly. Open Source is a bit more trustworthy that way!
For anyone who missed it, here's the document. Please edit! http://linux.wikia.com/wiki/Open_Source_Software_in_Government_and_Education
Cheers,
- Ashwin.