To vacate old small shop tenants

Dear Experts,

Two tenants occupying two separate shops, in a portion of an old building, They are in possession of the shops for a very long time, that is to say more than 40 years.  Rest two shops are vacant  for around 10 years in the building. The back portion of the building is occupied by us for taking tuition etc. We are staying in another old house in the same compound.

They are paying rent. Needless to say they are paying very small amount as rent. One shopkeeper keeps a book, to record payment of rent on which we will put signature. Other tenant pays by cheque now.

There are no rent agreement or anything available. We want to demolish the old building for a new building. How to vacate them? will there be any difficulties in vacating them since they are occupying for very long time.

Will the law favor them by adverse possession?

please advice me what is the procedure to get  them to vacated?