Our apartment building has 5 floors, and the penthouse owner on the 6th floor has blocked the staircase, claiming ownership of the terrace. Is this legal, given the penthouse itself might be illegal? What options do we have to regain access to the stairs? Could we file a police complaint against the penthouse owner?

In India, blocking common areas like staircases is illegal, regardless of the penthouse’s legality. You can file a complaint with the local municipal corporation or housing society, and if necessary, pursue legal action to regain access. A police complaint might be considered if the blocking causes immediate danger or disrupts public order.