Hi
1) Since the rental agreement is not registered either under the Tamil Nadu Regulations of Rights and Responsibilities of Landlords and Tenants Act 2017 or under the Registration act, despite the fact that the tenant has been conducting the business in your premises for more than 10 years, it will be construed as month on month tenancy which is very favourable to you in the present case.
2) It is the stated position of law, In the absence of registration, the period specified in the lease deed cannot be taken into account or relied on and such lease will tantamount to an oral lease .
3) However, it is also the state position of law, that even in the absence of registration of an agreement of lease entered into between the parties, it can be reasonably presumed that the lease is on a month to month basis, as has been contemplated under Section 106 of The Transfer of Property Act.
4) So, You are entitled to claim the amount mentioned in the unregistered lease agreement as your rental dues and you should claim the rental arrears based on the amount mentioned in the unregistered lease agreement.
5) In Tamil nadu, since Tamil Nadu Regulations of Rights and Responsibilities of Landlords and Tenants Act 2017 was passed in the year 2017, standard rent fixed by municipal authorities will not be applicable in your case and your case needs to be contested based on civil contracts act , specific relief act only and not under tenancy laws.
6) The eviction suits in courts at Coimbatore or any wherein Kongu Mandalam take anywhere between 18-24 months, but, at the time of filing of eviction suit itself, you can file an Interlocutory application with a prayer to direct the tenant to deposit the rental amount in court month on month and you can collect the monies from the court. So, that way , your tenant will come under pressure to pay rents regularly on monthly basis through court, failing which his case will be dismissed.
Hope this information is useful.