How do i know if the Khata given by my seller is real or fake?

The only way you can cross-verify if the Khata is fake or genuine is by physically visiting the relevant BBMP or Gram Panchayat office. If you can't do it yourself then get in touch with experienced advocates who can do it for you.

Apply for khata certificate and khata extract from the BBMP office. If nothing comes out. It means, it is fake. It might have been the case your poor seller might have been cheated himself. :)