Someone has illegally entered my farm land in Kolkata and is not leaving what to do

Criminal trespass is punishable under Section 329 of the Bharatiya Nyaya Sanhita, and if the trespass is in a dwelling, the offense is more serious. You should file an FIR at the nearest police station in Kolkata, providing land records and photographs showing the illegal entry. Under West Bengal Premises Tenancy Act 1997, there may be additional provisions for agricultural land protection. You can also file a civil suit for eviction and possession of the land before the appropriate court in West Bengal. If the police do not act on your complaint, you can approach the Calcutta High Court for a writ of mandamus directing police action.