I live on the fourth floor in Delhi with my parents for 13 years. My neighbours who live below us have been creating nuisance and giving us threats.
We have installed a duct in our shaft for our air cooler for last 12 years . And no one has had any objections for the same but for the last one month , our neighbours have been threatening my parents saying it's illegal and we should remove it .
When we asked our other neighbours they said they have no problem with the duct .
And yesterday the lady who lives below said to my parents "Now see what I can do , you'll repent it . Now stop me if you can."
They have been making false narratives that they aren't able to breath because of it.
Her son shoutes and curses us at his home .
What steps should I take for the same?