How can we evict a non authorized person who is not tenant from our plot?

Sir, It is happened that, in 1926, my grandfather purchased land at the court auction, where he come to possession of two plots which is of total 40 cents. Where one plot which we are residing now ancestrally is of 33 cents plot. Another plot is nearby which is 500 yards away and at 11 cents (out of which only 7 cents allotted to our grandfather, 4 cents were taken by another person, but under single RTC of 11 cents). At the time of purchase from the court, 33 cents plot was vacant and was duly occupied by my grandfather, but, 7 cents plot was occupied by those who in the first place took bank loan on the said property and couldn't repaid and hence that plot went to auction in the court. So, after the purchase, my grandfather didn't vacate them from the place, instead provided it on rent basis to them as they had no other place to go to. Years gone by, first they were giving rents when my grandfather was there, but in 1961 my grandfather died, later my father and his brothers went to Mumbai in search of job from my native place, leaving behind only grand mother and sisters. Slowly as the sisters left native after the wedding, there were no people to ask rent and rent also stopped. Our most of the extended family now resides in Mumbai, but my father chose to come to native, but then, since lot of time is over, there were relatives of the original rental family was living in 7 cents plot and they were totally ignorant of these rental setting and my grandfather’s name was also with others (those who primarily lend plots to the bank) in both the RTCs (33 cents, and 7 cents) due to formalities after possession was not completed by my grandfather. But then thankfully, we had original sales certificate and court judgement from 1926 and we preserved it carefully and presented it to the District Magistrate to change the title of the land to our grand father's name. This went all legal process as required like checks and newspaper ad etc. and then transferred to grand father's name. Now again property was transferred to my father's and his sister's possession under joint holding. Now the RTC bears the name of my father and his sisters in joint over both the plots. But when my father found that door number name for 7 cents plot was in old possessor's name, who was there for rent after my grandfather’s purchase of that plot. Father wanted to change the door name and to evict the people who are not even close relatives of the original possessors but still occupied that plot because of our absence in the native place. But town municipal corporation is not changing the door number and name to our joint holder’s name, giving reason that there is not empty plot, there is house there and it was originally 11 cents plot and it has to surveyed and marked by govt. surveyor. But when surveyor come, resident of that 7 cents plot yelling, threatening and drove away surveyor. Now how to evict this unauthorized, not close relative from occupied plot?