Leakage from flat.

We've been staying in western suburbs of Mumbai on the first floor of a building that is about 40 years old. We've changed the pipe line about 15 years ago and made it concealed. Also, have changed the flooring of the bathroom to red tramite and applied tiles to the wall during the same time. Now there is a leakage which is sipping in a flat beneath us and the flat owner and the society wants us to remove the apparent leakage. My question is, in case of me repairing my bathroom for removing leakage, will the owner if the flat beneath me liable to share 50%expenses. Any legal citations or bylaws to that effect shall be highly appreciated. PS.: Our society has maintained that I need to take the necessary action as and that the society is not liable for the expenses or taking any corrective actions.