Tenant living in our ancestral property for 35 yrs - Not Vacating

Tenant Living in our grandfathers house for around 35 years. My Father has been asking him to vacate the house verbally from the past 5 years and he is not vacating. He is using front portion of the house for his jewellery business for many years now and was using back portion of the house for living. In the last couple of years, he has got his own house constructed in a different place and a different Jewellery shop in his son's name. He is not using our house for living and making one of his servant sleep in that house. He is still continuing his business in our house and his son is sitting in his new shop. He is not saying NO but also not vacating. Earlier he asked time for constructing his house and then 1 year for constructing his new shop and now he has asked 6 months again. He is being rude saying do whatever we want but wont leave house for 6 more months. Also the last agreement made between him and my father was in 1992 and was never renewed. He is paying rent in cash just 1000rs which is way too low as per market standards and only when we ask him to pay. We want to use this house for our personal use now. He has asked time till june 2017. We wanted to avoid legal approach as it may take years for the outcome. if he doesnt vacate by June 2017, i think going legal is the only option. Also, he keeps on threatening about his connections as he is local leader of a political party. Please suggest what should be the course of action on this to get our property back.