Section 36 in THE BHARATIYA NYAYA SANHITA, 2023 – BNS

Right of private defence against act of a person of unsound mind, etc.

36. When an act, which would otherwise be a certain offence, is not that offence, by
    reason of the youth, the want of maturity of understanding, the unsoundness of mind or the
    intoxication of the person doing that act, or by reason of any misconception on the part of
    that person, every person has the same right of private defence against that act which he
    would have if the act were that offence.
    Illustrations.
    (a) Z, a person of unsound mind, attempts to kill A; Z is guilty of no offence. But A has
    the same right of private defence which he would have if Z were sane.
    (b) A enters by night a house which he is legally entitled to enter. Z, in good faith,
    taking A for a house-breaker, attacks A. Here Z, by attacking A under this misconception,
    commits no offence. But A has the same right of private defence against Z, which he would
    have if Z were not acting under that misconception.