(1) There is no right of private defence,––
(a) against an act which does not reasonably cause the apprehension of death or of grievous hurt, if done, or attempted to be done, by a public servant acting in good faith under colour of his office, though that act, may not be strictly justifiable by law;
(b) against an act which does not reasonably cause the apprehension of death or of grievous hurt, if done, or attempted to be done, by the direction of a public servant acting in good faith under colour of his office, though that direction may not be strictly justifiable by law;
(c) in cases in which there is time to have recourse to the protection of the public authorities.
(2) The right of private defence in no case extends to the inflicting of more harm than it is necessary to inflict for the purpose of defence.
Explanation 1 — —A person is not deprived of the right of private defence against an act done, or attempted to be done, by a public servant, as such, unless he knows or has reason to believe, that the person doing the act is such public servant.
Explanation 2 — —A person is not deprived of the right of private defence against an act done, or attempted to be done, by the direction of a public servant, unless he knows, or has reason to believe, that the person doing the act is acting by such direction, or unless such person states the authority under which he acts, or if he has authority in writing, unless he produces such authority, if demanded.
Legal Commentary & Landmark Judgments: Section 37
Private defence is a protective shield, not an offensive weapon or an instrument of private vengeance. This section establishes the three categorical statutory restrictions limiting its exercise: first, no right exists against an act done or attempted by a public servant acting in good faith under colour of office, though not strictly justifiable by law, provided the act does not cause reasonable apprehension of death or grievous hurt; second, no right exists against acts done under the direction of such a public servant; third, no right exists where there is reasonable time and opportunity to seek the protection of public authorities. Furthermore, Section 37(2) enacts the cardinal Proportionality Doctrine: the right of private defence in no case extends to inflicting more harm than is strictly necessary for defence.
Section 37 establishes the negative boundaries and operational limits of private defence under Indian criminal jurisprudence. It ensures that the right of self-preservation cannot be abused to resist lawful public administration or inflict disproportionate retributive violence.