I investigated further. It works fine on Mac and Windows 8.1. Apparently your operating system doesn't support the CA yet. I don't have Ubuntu, but I do have a linux based system, and it fails there too.
They are using a relatively new sub-CA of e-Mudhra, so it will appear everywhere soon, I believe.
If you're really willing to use it now, SHA1 of verified certificate is 56 7F 2D B5 7E 31 BC E5 6C 5C 8C 3B 80 44 AA 2F 7C 13 D3 6D. Not ideal way at all, but might help paranoia. You shouldn't trust me though.
The Certificate seems to be verified by a "Gujarat Narmada Valley Fertilizers Company Ltd."
Speaking as an Indian, I am not sure i would trust a CA run by a company that is close to the Indian govt. (whose record on corruption and civil liberties isn't exactly stellar).
The whole point of the CA system is that there is no place for personal opinion on which CA to trust, as long as they make it to your operating system. The audits they go through far trumps the hand waiving you just did.
They are using a relatively new sub-CA of e-Mudhra, so it will appear everywhere soon, I believe.
If you're really willing to use it now, SHA1 of verified certificate is 56 7F 2D B5 7E 31 BC E5 6C 5C 8C 3B 80 44 AA 2F 7C 13 D3 6D. Not ideal way at all, but might help paranoia. You shouldn't trust me though.