Bharatiya Nyaya Sanhita, 2023 · Chapter III: General Exceptions
Section 17: Act done by a person justified, or by mistake of fact believing himself justified, by law
In plain words
An act is not an offence if the law justifies it, or if the person honestly believed it was justified because of a mistake about the facts. A mistake about the law does not count.
Example: A sees Z apparently committing a murder and seizes Z to hand over to the authorities. A commits no offence, even if it later turns out Z was acting in self-defence.
A simplified explanation, prepared with AI assistance from the official text below and checked automatically against it for numbers and cross-references. The official text is the law and prevails over this summary. Not legal advice.
Read the in-depth explanation, with key Supreme Court rulings ↓
Official text
Nothing is an offence which is done by any person who is justified by law, or who by reason of a mistake of fact and not by reason of a mistake of law in good faith, believes himself to be justified by law, in doing it.
Illustration
A sees Z commit what appears to A to be a murder. A, in the exercise, to the best of his judgment exerted in good faith, of the power which the law gives to all persons of apprehending murderers in the fact, seizes Z, in order to bring Z before the proper authorities. A has committed no offence, though it may turn out that Z was acting in self-defence.
Corresponding sections were matched by comparing the wording of both official texts, and for the IPC and BNS, also against a published correspondence table. Wording, punishments and structure often changed, so read both sections before relying on the match.
Source: India Code (indiacode.gov.in), the consolidated text published by the Legislative Department, Government of India. Text as updated on India Code on 25 August 2026. Words in square brackets [ ] were inserted or substituted by later amending Acts, and *** marks words omitted by an amendment. The amendment footnotes are not reproduced here. Official text on India Code.
Understanding this section
Section 17 carries forward section 79 of the IPC without change in substance: an act done by a person justified by law, or who by a mistake of fact (not of law) in good faith believes they are justified by law, is not an offence.
Key points
- Only a mistake of fact helps; a mistake of law does not.
- Good faith requires due care and attention, so a careless belief fails.
- The accused must bring the case within the exception (section 108 of the Bharatiya Sakshya Adhiniyam, the old section 105 of the Evidence Act).
Key Supreme Court rulings
Satyavir Singh Rathi v. State through CBI 2011 INSC 347
Decided under section 79 of the IPC. Police officers who fired on innocent citizens, mistaking them for a criminal, could not claim the exception; the firing was in furtherance of their common intention.
Common mistakes
- Pleading the section for a misunderstanding of what the law allows.
Read with: Section 14 BNS, Section 79 IPC
Prepared with AI assistance as a study aid. Every ruling listed was checked against the Supreme Court's own judgments on this site, and quoted words appear in those judgments; linked names open the full judgment. Read the judgments themselves before relying on them. Not legal advice.
Supreme Court judgments citing the section 17
No Supreme Court judgment in our database cites this section yet.