Accident, Necessity and Consent as Defences Under the BNS

Under the Bharatiya Nyaya Sanhita, 2023 (BNS), accident is a defence under Section 18, necessity under Section 19, and consent under Sections 25 to 30, all within Chapter III on General Exceptions. Each defence has strict conditions: an accident must happen while doing a lawful act with proper care, a necessity act must be done in good faith without criminal intention to avoid other harm, and consent must be free, informed and given by a person legally able to give it. These provisions carry forward the old IPC Sections 80, 81 and 87 to 92 almost word for word, so the case law decided under the IPC still guides how courts read them.

This explainer is for B.A. LL.B. and LL.B. students preparing for criminal law papers, and for any citizen who wants to know when causing harm is not a crime. It matters in daily life: a surgeon operating in an emergency, a driver swerving on a narrow road near Marthandam, or two friends sparring at a boxing club in Nagercoil all raise the same question. Was this an offence, or does the law excuse it?

Where do these defences sit in the BNS?

The BNS came into force on 1 July 2024 and replaced the Indian Penal Code, 1860. The General Exceptions moved from Chapter IV of the IPC to Chapter III of the BNS. The ones covered here are:

• Section 18: accident in doing a lawful act (old IPC Section 80).
• Section 19: act likely to cause harm, done without criminal intent to prevent other harm, that is, necessity (old IPC Section 81).
• Section 25: act not intended and not known to be likely to cause death or grievous hurt, done with the consent of a person above eighteen (old IPC Section 87).
• Section 26: act not intended to cause death, done in good faith with consent for the person's benefit (old IPC Section 88).
• Section 27: act done in good faith for the benefit of a child under twelve or a person of unsound mind, by or with the consent of the guardian (old IPC Section 89).
• Section 28: when consent is not valid (old IPC Section 90).
• Section 29: acts that are offences independently of the harm caused (old IPC Section 91).
• Section 30: act done in good faith for a person's benefit without consent, when consent cannot be obtained in time (old IPC Section 92).

The wording is close to the IPC, but always quote the BNS text in your answer, not the old section.

When is an accident a defence?

Section 18 says nothing is an offence which is done by accident or misfortune, without any criminal intention or knowledge, in doing a lawful act in a lawful manner by lawful means and with proper care and caution. Break that into four checks:

1. The harm happened by accident or misfortune.
2. There was no criminal intention or knowledge.
3. The act itself was lawful and done in a lawful manner by lawful means.
4. The person took proper care and caution.

The illustration in the Sanhita is of a man working with a hatchet whose head flies off and kills a bystander. If he took proper care, he is excused. If the hatchet was loose and he knew it, the fourth condition fails. That last condition is where most cases are lost. A carpenter in Kanyakumari who uses a cracked tool near a crowd cannot later call the injury an accident.

What does necessity require?

Section 19 protects a person who does something knowing it may cause harm, if it is done without criminal intention to cause harm, in good faith, to prevent or avoid other harm to person or property. The Explanation makes it a question of fact whether the harm avoided was so serious and so imminent that the risk was justified. The Sanhita's illustrations include a ship's captain changing course to save many lives at the risk of fewer, and pulling down houses to stop a fire from spreading.

The defence is narrow. In Dalel Singh v. State of H.P. (decided 12 March 2026), the Himachal Pradesh High Court refused the necessity plea of a bus driver who swerved to avoid a cyclist and killed two motorcyclists on the other side of the road. The court treated the swerve as an admission that the bus was on the wrong side and held that a person cannot claim necessity when avoiding harm to one causes greater harm to others. This is a High Court ruling, so treat it as persuasive, but it shows how courts weigh the harm caused against the harm avoided.

How does consent work as a defence?

Consent is a group of provisions, and you must read them together.

• Section 25 covers harm the doer neither intended nor knew was likely to cause death or grievous hurt, where the person harmed is above eighteen and consented, expressly or impliedly. Sports such as fencing are the classic example.
• Section 26 covers harm, short of intended death, done in good faith for the benefit of a consenting person. The surgeon who performs a risky operation with the patient's consent is the standard illustration.
• Section 27 extends protection to good faith acts for children under twelve and persons of unsound mind, with the guardian's consent, but not to intentional killing or voluntary grievous hurt except to prevent death or cure a grievous disease.
• Section 30 covers emergencies: harm caused in good faith for a person's benefit even without consent, where the person cannot consent and no guardian can be reached in time. Its Explanation states that mere pecuniary benefit is not "benefit" for Sections 26, 27 and 30.

Section 28 then tells you when consent is no consent at all: if given under fear of injury or a misconception of fact that the doer knew or had reason to believe, if given by a person who cannot understand its nature because of unsoundness of mind or intoxication, or if given by a child under twelve. Section 29 adds that consent does not cover acts that are offences on their own, regardless of harm, such as causing miscarriage except in good faith to save the woman's life.

Which Supreme Court cases should you know?

Two decisions come up repeatedly in exams and in practice.

• Jacob Mathew v. State of Punjab, (2005) 6 SCC 1, decided 5 August 2005. A three judge bench led by Chief Justice R.C. Lahoti referred to Sections 88, 92 and 93 IPC as protections for doctors acting in good faith, and held that criminal liability for medical negligence needs negligence of a gross or very high degree. A simple error of judgment or an accident is not enough. Under the BNS, death by negligence now falls under Section 106, which keeps a lower maximum of two years for registered medical practitioners.
• Pramod Suryabhan Pawar v. State of Maharashtra, (2019) 9 SCC 608, decided 21 August 2019. On consent obtained by a promise of marriage, the Court laid down a two part test: the promise must have been false and in bad faith from the start, and it must have had a direct link to the woman's decision. The Madras High Court applied this test in Ravi v. State (Crl. R.C. No. 126 of 2017, decided 29 July 2022) and set aside a conviction where the evidence showed only a later breach of promise.

How should you write about this in an exam?

1. Start with the BNS section and quote its key words. Mention the old IPC section once, in brackets.
2. List the ingredients as numbered conditions, as done above for Section 18.
3. Use the illustration from the Sanhita, then add your own short example.
4. Cite one or two cases with correct names and years. Do not guess a citation.
5. For problem questions, test each condition against the facts and say clearly which one fails.
6. Remember the burden. Under Section 108 of the Bharatiya Sakshya Adhiniyam, 2023 (old Section 105 of the Evidence Act), the accused must prove that the case falls within a General Exception, and the court presumes it does not until that is shown.

If you want to see how these defences arise in real disputes, the college legal aid clinic is a good place to observe case work.

Sources

• India Code: The Bharatiya Nyaya Sanhita, 2023: official record of Act 45 of 2023, enforced from 1 July 2024.
• PRS Legislative Research: Bharatiya Nyaya Sanhita, 2023 (Bill text): text of the General Exceptions chapter as introduced in Parliament.
• India Code: The Bharatiya Sakshya Adhiniyam, 2023: official record of Act 47 of 2023, including Section 108 on the burden of proving a General Exception.
• Indian Kanoon: Jacob Mathew v. State of Punjab (2005): full judgment on medical negligence and good faith.
• The Tribune (26 December 2023): report on BNS Section 106(1) and the two year limit for registered medical practitioners.
• Indian Kanoon: Ravi v. State (Madras High Court, 2022): application of Section 90 IPC and the two part test from Pramod Suryabhan Pawar (2019).
• LiveLaw: HP High Court on necessity (2026): report of Dalel Singh v. State of H.P.