Rent Increase from Landlord

Hi, I live in Pune at a Rented Apartment and have been staying here since last two months. I have a Registered Leave and License with my Landlord. It is a 2 BHK house with 18k rent and a security deposit of 50k with a lock-in period of 1 year. The house had a water problem inherently and was not communicated to us. We communicated the same to him and requested to put a Water Tank inside the Bathroom for emergency situation. He agreed and did the needful. After 10 days of that, he suddenly called and said that he has decided to increase the rent by 2k. It was not communicated to us neither verbally nor in writing while the Water Tank was being put that the rent is going to increase. I said that I will not be able to pay him extra rent. To that he said that then I will have to evict the house. I said that I am willing to do so if he pays my security deposit back, to which he is saying that he will deduct one month rent. Nothing is mentioned in the Agreement regarding the increase in Rent. He is harassing me and my wife who says alone in the Flat. What should I do? Please help me out.