It's somewhat normal to need this sort of documentation to perform background checks, credit checks, or other steps required for new employees in some industries.
Of course, you want to be sure you are talking to a legitimate employer, not a scammer pretending to be hiring new employees. This should be pretty obvious if you've performed interviews with a legitimate company, versus, say, having responded to an online add for a company name you've never heard of, and then meeting someone in a temporary office set up in a hotel room - or anything else sketchy.
To get to your actual question - you asked,
Should I send them as an email
Email may not be the best choice for sensitive documents, at least not email that isn't somehow secured. If the employer cannot offer a secured mechanism (i.e. a secured online portal, or a secure messaging or email system), then you may want to do some quick googling to come up with your own method. At the very least, a password-protected archive (zip) with the password supplied separately via phone call provides at least basic protection, in case anyone has access to your emails.
You also asked,
or is it my right not to send it
You certainly have the "right" to refuse sending it, but the employer also has the right to tell you they can't hire you as a result.
I have never been asked so many things prior to signing a contract.You're never worked in India then. :)