New owner - tenants staying from more than 25 years from previous owner - adverse posession

A tenant can never claim adverse posession. 

In the given facts, the rent agreement needs to be registered. In my understanding, notarised rent agreement does not satisfy the requirments of law.

Refusal to renew the rent agreement and/or non-payment of rent is sufficient and substantial grounds to seek eviction.

1. There's no provision in law for the tenant to claim title by adverse possession because he is paying the monthly rental amount regularly, hence his possession is by virtue of tenancy and not adverse. 

2. You issue them a legal notice stating that you are the new owner to the property hence they have to get a new rental agreement entered into immediately otherwise to vacate the premises within two months from this date and deliver vacant possession. 

3. You may follow the steps suggested above which will fetch you the desired remedy. 

If there is rent agreement then they cannot calim the adverse possesion, however the rent laws are applicable,

You have made new rental agreements for all the tenants. Does that include the 3 tenants also? Have they signed the new rental agreement or do they refuse to sign the agreement?  You say that they are shops. Shops are commercial establishments. When a shop oprates for a long time from a locality, they earn the goodwill of the local residents who will be his customers. If you ask them to vacate without sufficient reason, they can refuse or claim compensation. Commercial establishments are different from residential establishments. I do not know the law in this regard. The learned lawyers can advise you.