How To Transfer & Register A Residential Property In Noida On 2nd PoA

I have a residential property (flat) in Noida, Uttar Pradesh which I want to register so that I can sell it. I bought it in the year 2000 from a property broker and I have the second power of attorney (both general and special). First PoA was concluded between the property broker and the registered owner, and then the property broker sold it to us on 2nd PoA. I don't have any contact with the registered owner, neither am I able to find him. In this case, how do I transfer and register this property in my name, without the need of the last registered owner? Also, the property broker is not willing to transfer through him to us as this would result in capital gains tax for him. Also, I'm not sure if this is even legal.