Repairing of damage roof in a rented house

We have been tenant in this building before 1976. The building is located in a very prime location in bhowanipore and is more than 100 years old. The present landlord use to collect rent 5 times more than what it use to be according to the fair rent policy but after an year or so he stopped collecting rent and stopped all contacts with us so we eventually started depositing the rent in rent control. Now the problem is the building is too old and it has become very dangerous place to reside.Apart from leaking roofs the terrace is in so dangerous condition that it might fall off and create casualties. My mom and dad are too old and I am very scared of them once I leave the house for work. We want to repair the place but land is constantly creating obstacles and not letting us complete the work. We have been told that it takes 6 months or may be more to get a permission done from the repairing dept however anything can happen within that time so my question is will the law wait for any casualty and then come to a decision?