How to evict my tenant legally?

My father has a property in a small town of West Bengal. Where he rented two stalls to two tenant in1991. The rent is very minimal (approx. 600/- per month) where the rent should be atleast ₹8000 to ₹12000 per month considering the rents of adjacent property. The agreement between two parties have some visible faults. eg.1. The agreement is not registered or notarized.2. The agreement have no time limit.3. One of two tenants has changed his business which he can't do without written consent of the landlord as per the agreement, which obviously he doesn't have.Upon this they falsely accused us for not accepting the rent and went to the rent controller which is still under judgement of Honourable SDO.In this situation what should be done to evict the tenants as we really want the property for personal use?nThank You.