What is protected tenant in pagdi system?

Respected Experts

I am landlord and building owner with pagdi tenants who are not co-operating for redevelopment. Many tenats have no agreements. Some tenancy changes have happened even as late as 2003. 

I want to know what is Protected tenant and what is unprotected tenant. Some old tenants got in newer tenant in r year 1990..some even as late as 2007 ,  and we also have a rent agreements, can we evict him?

Your feedback will be valuable. Regards