Tenant refusing to evict shop

My late grandfather rented out a shop to a tenant 40 years ago without any formal rent agreement, which was common at the time. The shop is built on leased property. Around 10–15 years ago, the tenant constructed a much larger shop (6–7 times the size of ours) right in front of our shop. Despite this, he refused to vacate our property, even after repeated verbal requests. After lengthy negotiations, the tenant agreed to vacate half of the shop, under rent for their use as a warehouse and we got other half (We now operate a disposable goods business in the part we regained). As part of this compromise, a proper rent agreement was made, stating that the tenant would pay ₹1.5 lakh for renovation/reconstruction, which would then be adjusted against the rent (1500rs/month which is way less then actual value but agreed as we want possession of shop somehow). However, the agreement does not specify a time limit for his use of the property. (During the renovation, the tenant filed a legal case against us, alleging that we were not giving him access to the half shop which is causing him financial losses, even though it was still under construction/renovation. A proper legal case ensued, and the tenant won. Notably, he told the court that his son was running the larger shop (which is 6–7 times the size of ours) to gain sympathy, but in reality, the shop belongs to him.) We now want to reclaim the entire shop (which he will refuse ). What legal options do we have? Any advice would be greatly appreciated!