Section 436A CrPC, now carried forward as Section 479 of the Bharatiya Nagarik Suraksha Sanhita, 2023, requires an undertrial to be released on bail once detention crosses one-half of the maximum sentence for the offence, and bars detention beyond the full term. First-time offenders under Section 479 qualify at one-third, but the relief does not reach offences punishable with death or life imprisonment.
In 2025 the Supreme Court pressed States and Union Territories to take proactive steps to identify and release eligible undertrials under Section 479 BNSS, and the Ministry of Home Affairs told prisons to use the provision on a continuous basis to ease overcrowding. This followed the Court’s 2024 direction that Section 479 applies to undertrials whose cases were registered before the new code came into force on 1 July 2024. The push matters because eligible prisoners were sitting in jail unidentified, which is exactly the harm the provision was written to prevent.
This article sets out what Section 436A CrPC guarantees, who qualifies and who is shut out, how Section 479 BNSS changed the rule, and how an undertrial actually secures release.
What Section 436A CrPC provides on maximum detention of an undertrial
Section 436A of the Code of Criminal Procedure, 1973 directs that an undertrial detained for one-half of the maximum imprisonment prescribed for the offence must be released by the court on a personal bond, and can never be detained beyond the full maximum term. Parliament inserted it by the Code of Criminal Procedure (Amendment) Act, 2005, and it took effect on 23 June 2006. The trigger was the mass of undertrials held for years while the presumption of innocence still ran in their favour.
The section does three separate things, and it helps to keep them apart. It fixes a one-half point at which release becomes the rule, it fixes an outer ceiling that detention can never cross, and it carves out the most serious offences.
The one-half rule and release on personal bond
The one-half rule releases an undertrial once time in custody during investigation, inquiry or trial reaches half the maximum sentence for the offence. Release is on the person’s own bond, with or without sureties, which means the court does not treat this as an ordinary bail hearing where the accused argues merit. The detention itself, measured against the statutory maximum, is the ground.
The word “maximum” is doing the work here. For an offence carrying up to seven years, the half-point is three and a half years; for one carrying up to ten years, it is five. The calculation runs on the ceiling the statute sets, not on the sentence the accused might finally receive.
The outer limit on detention beyond the maximum sentence
The outer limit bars detention during investigation, inquiry or trial for longer than the maximum period of imprisonment fixed for the offence. This is an absolute cap and sits above the court’s discretion. An undertrial cannot be held pending trial for longer than the sentence a conviction could ever produce.
The two thresholds work in sequence. The one-half point is where release becomes presumptive and the court may still order continued detention for recorded reasons; the maximum-term point is where detention must stop, with no discretion left.
Offences the section does not cover
Section 436A does not apply where the offence is punishable with death as one of the possible punishments. For that narrow class, the one-half rule gives no automatic route out, and the undertrial must seek bail on ordinary grounds. Everything below that line, across any statute, is within the section’s reach.
The exclusion is drawn by the punishment the offence carries, not by the label of the statute. If death is on the menu of sentences for the offence, the section steps aside; if it is not, the section applies even to grave charges.
Section 436A CrPC at a glance
The undertrial’s maximum detention rule in three parts
Release at half the term
Detention of one-half of the maximum sentence for the offence triggers release on a personal bond, with or without sureties.
No detention past the maximum
An undertrial can never be held during investigation, inquiry or trial for longer than the maximum sentence the offence carries. This cap is absolute.
Death-punishable offences out
The one-half rule does not apply where death is one of the possible punishments. Section 479 BNSS widens this to life-imprisonment offences too.
Who is eligible for release under Section 436A, and who is excluded?
An undertrial is eligible once custody crosses one-half of the maximum sentence, except where the offence is punishable with death, and the clock is cut by any delay the accused caused. Eligibility does not depend on the strength of the prosecution case. It depends on arithmetic: time served against the statutory maximum, minus the delay the accused is responsible for.
Detention during investigation, inquiry or trial counts
The half-period counts custody across investigation, inquiry and trial together, not just the trial phase. Time in judicial custody from the point of first detention feeds the calculation, so an undertrial does not restart the count when the case moves from investigation to committal to trial. This is what lets long pre-charge detention count towards the threshold.
Delay attributable to the accused is excluded
Delay the accused causes is stripped out of the half-period before the threshold is tested. If the undertrial sought repeated adjournments, absconded, or otherwise held up the proceedings, that time does not count towards the one-half. The provision protects an undertrial trapped by a slow system, not one who engineered the slowness.
Courts read this strictly against gaming and generously towards genuine delay. The burden of showing that lost time was the accused’s own doing sits with the prosecution, because the default is that institutional delay counts.
The court’s proviso power to continue detention
The proviso lets the court, after hearing the public prosecutor and recording reasons in writing, keep an undertrial in custody beyond the one-half point or release on bail rather than a bare personal bond. This is the safety valve for cases where release at the half-point would be dangerous or the record justifies stricter conditions. What it cannot do is push detention past the outer maximum-term ceiling, which no reasons can lift. Where a court is weighing conditions or cancellation instead of a clean release, the framework in iPleaders’ guide to cancellation of bail under the BNSS sets out how that discretion is structured.
Section 479 BNSS: how the successor provision changed the rule
Section 479 of the Bharatiya Nagarik Suraksha Sanhita, 2023, in force since 1 July 2024, keeps the one-half rule but adds a one-third threshold for first-time offenders, bars release where cases are pending in more than one offence, widens the exclusion to life-imprisonment offences, and puts a duty on the jail superintendent to move the application. It is the operative provision today. Section 436A CrPC stands repealed with the rest of the old code, though it still governs conduct and computations that predate the switch and remains the reference point courts reason from.
The one-third rule for first-time offenders
Section 479 releases a first-time offender on bond once custody reaches one-third of the maximum sentence, rather than one-half. A first-time offender for this purpose is someone never convicted of any offence in the past. This is the single most consequential change, because it moves the release point forward for exactly the undertrials least likely to be hardened repeat accused.
The mechanics mirror the one-half rule. The court releases on a bond on completion of the one-third period, subject to the same exclusions and the same proviso power to record reasons for continued detention.
The bar where cases are pending in more than one offence
Section 479 blocks release under the section where investigation, inquiry or trial is pending against the undertrial in more than one offence, or in multiple cases. Where that is the position, the court is not to release the person on bail under this provision, and they must fall back on ordinary bail. Section 436A carried no such express bar, so this is a genuine narrowing that has drawn criticism for shutting out undertrials with several minor cases stacked against them.
The jail superintendent’s duty to apply
Section 479 makes the superintendent of the jail apply to the court, in writing, for the release of an eligible undertrial once the one-half or one-third period is complete. The duty does not sit only on the prisoner or the defence lawyer, many of whom never file. Putting the obligation on the custodian is meant to reach the undertrials who have no one moving their case, and it is the mechanism the Supreme Court leaned on when it directed superintendents nationwide to process eligible prisoners.
Section 436A CrPC compared with Section 479 BNSS
Section 436A and Section 479 share the one-half rule and the outer detention ceiling, but Section 479 differs on four points that change who actually gets out. The shared core is the same: half the maximum sentence triggers presumptive release, delay by the accused is excluded, the court retains a reasons-recorded proviso, and detention can never cross the maximum term. The differences sit on top of that core.
The first difference is the one-third route for first-time offenders, which Section 436A never offered. The second is the exclusion: Section 436A only shut out death-punishable offences, while Section 479 also shuts out offences punishable with life imprisonment. The third is the express multiple-case bar in Section 479, on which Section 436A was silent. The fourth is the superintendent’s statutory duty to apply, which the old section did not impose on anyone.
Read together, the changes cut in both directions. The one-third rule and the superintendent duty widen access and push release earlier for first-timers, while the life-imprisonment exclusion and the multiple-case bar close the door on classes of undertrial who could earlier argue for the one-half benefit. For a fuller map of how bail categories are structured across these provisions, the LawSikho explainer on bail under the CrPC and BNSS walks through the types and thresholds.
Section 436A CrPC vs Section 479 BNSS
What the successor provision kept, and what it changed
| Feature | Section 436A CrPC | Section 479 BNSS |
|---|---|---|
| One-half rule | Release on personal bond at one-half of the maximum sentence | Retained: release on bail at one-half |
| First-time offender | No separate threshold | Release on bond at one-third of the maximum sentence |
| Excluded offences | Death-punishable offences only | Death and life-imprisonment offences |
| Multiple cases pending | Silent | Express bar: no release under the section |
| Who must apply | In practice, the accused | Jail superintendent has a statutory duty to apply |
| Outer detention cap | Never beyond the maximum term | Retained: never beyond the maximum term |
How does an undertrial actually get released under Section 479 BNSS?
Release runs on an application to the court that hears the case, moved by the undertrial, the defence, or the jail superintendent once the one-half or one-third threshold is met, after which the court hears the public prosecutor and orders release on bond unless a proviso bars it. It is not automatic in practice, even though the entitlement is statutory, because someone has to place the completed-period fact before the court.
Who moves the application and to which court
The application goes to the court before which the case is pending, and it can be moved by the prisoner, the defence lawyer, or the superintendent under the Section 479 duty. Because the superintendent now carries an independent obligation, an undertrial with no lawyer is no longer wholly dependent on filing their own petition. This is a change from the Section 436A regime, where in practice the burden of raising the point fell almost entirely on the accused.
What the court weighs before ordering release
The court checks the completed period against the maximum sentence, confirms the offence is not excluded, and confirms no multiple-case bar applies, then hears the public prosecutor before releasing on bond. Where the prosecutor opposes, the court can invoke the proviso and record reasons for continued detention past the one-half point. What the court is not doing is reweighing the merits of the charge, because the section runs on time served, not on guilt or innocence.
For undertrials facing a stringent special statute, the release calculus interacts with default bail and regular bail routes, which run on different clocks. The mechanics of the investigation-completion clock are set out in iPleaders’ explainer on default bail under Section 187(3) BNSS, and the ordinary route is covered in its guide to a regular bail application under Section 480 BNSS.
Why eligible undertrials still remain in jail
Eligible undertrials stay in custody mainly because of an identification gap: prisons and courts often do not flag who has crossed the threshold, applications are never filed, and multiple-case bars catch prisoners with several small cases. The Supreme Court itself found the process of identifying beneficiaries deficient, which is why it ordered superintendents to process applications rather than wait for prisoners to move. The gap is administrative, not legal, and it is the reason the 2024 to 2025 directions focused on machinery rather than on rewriting the rule.
Constitutional backing and the overcrowding problem
Section 436A gives statutory shape to the Article 21 right against indefinite pre-trial detention, which is why the Supreme Court has treated its underuse as both a liberty issue and a prison-overcrowding issue. The provision did not invent the protection. It codified a guarantee the Court had already read into the right to life and personal liberty.
Article 21 and the speedy-trial line of cases
The constitutional root is the speedy-trial guarantee the Supreme Court read into Article 21 in Hussainara Khatoon v. Home Secretary, State of Bihar, (1980) 1 SCC 81, which confronted undertrials held for years without trial. The Court held that a procedure depriving a person of liberty is not fair, just or reasonable unless it ensures a speedy trial. That reasoning is the direct ancestor of the one-half rule, which converts the abstract right into a hard time limit.
The line continued in the bail jurisprudence. In Union of India v. K.A. Najeeb, (2021) 3 SCC 713, the Court held that prolonged incarceration with no realistic prospect of an early trial lets a constitutional court grant bail even where a special statute restricts it, because the statutory rigour melts where the trial will not finish in reasonable time. The bail-guideline framework in Satender Kumar Antil v. CBI, (2022) 10 SCC 51 then folded these threads into a working set of categories courts apply across offence types. The landmark bail judgments for judiciary aspirants collect this line in one place.
Undertrials as a share of the prison population
Undertrials make up roughly three-quarters of India’s prison population, which is what turns Section 479’s underuse from a technical lapse into a mass-detention problem. When most people behind bars are unconvicted and a statutory release valve exists but goes unused, the overcrowding is largely self-inflicted by the system. That is the arithmetic behind the Ministry of Home Affairs advisory and the Supreme Court’s repeated directions to actually apply the provision. The wider picture of who is held and why is set out in iPleaders’ analysis of the state of prisons and undertrial incarceration in India.
Frequently asked questions
Is Section 436A CrPC still in force after the BNSS?
Section 436A CrPC stands repealed along with the rest of the Code of Criminal Procedure, 1973, and its successor is Section 479 of the Bharatiya Nagarik Suraksha Sanhita, 2023, which took effect on 1 July 2024. Section 436A remains relevant for understanding the provision’s origin and for cases governed by the earlier code, but the operative rule for undertrials today is Section 479.
Does the maximum-detention rule apply to offences punishable with life imprisonment?
Under Section 479 BNSS, no: the section excludes offences punishable with death or life imprisonment, so the one-half and one-third rules do not offer an automatic route out for those offences. Under the older Section 436A, only death-punishable offences were excluded, and life-imprisonment offences were not carved out in the same terms. An undertrial charged with such an offence must seek bail on ordinary grounds.
Can an undertrial be released before completing one-half of the maximum sentence?
Yes, in two situations. A first-time offender who has never been convicted can be released on bond under Section 479 BNSS at one-third of the maximum sentence, and any undertrial can separately apply for regular or default bail on ordinary grounds at any stage, which does not depend on the one-half or one-third thresholds at all.
Does Section 479 BNSS apply to cases registered before 1 July 2024?
Yes. The Supreme Court held in 2024 that Section 479 applies to undertrials across the country, including those whose cases were registered before the BNSS came into force on 1 July 2024, and directed jail superintendents to process eligible prisoners. The benefit is not limited to offences committed after the new code took effect.
What happens if the accused has more than one case pending?
Section 479 BNSS bars release under the section where investigation, inquiry or trial is pending against the undertrial in more than one offence or in multiple cases. In that situation the one-half and one-third rules do not apply, and the undertrial must pursue ordinary bail in each case instead. This express bar is one of the main differences from the older Section 436A.
References
Case Law
- Hussainara Khatoon v. Home Secretary, State of Bihar, (1980) 1 SCC 81
- Satender Kumar Antil v. Central Bureau of Investigation, (2022) 10 SCC 51
- Union of India v. K.A. Najeeb, (2021) 3 SCC 713
Statutes
- The Code of Criminal Procedure, 1973 (Section 436A)
- Bharatiya Nagarik Suraksha Sanhita, 2023 (Section 479)
- Constitution of India (Article 21)
Secondary sources
This article is for informational and educational purposes only and does not constitute legal advice. For advice on a specific case, consult a qualified advocate.
