Section 31 of the Patents Act, 1970
Anticipation by public display, etc.
Section 31 gives a twelve-month window after a notified exhibition or a learned society paper before that disclosure counts against you.
Official legal text
The verbatim statutory text of this provision is reproduced from the official source and checked by our legal reviewer before it is published here. Until that check is complete for this page, read the exact wording directly from the official source linked below — it is the only version that governs.
This is a simplified explanation. Where it differs from the official text of the provision, or from an applicable Gazette notification, the official text and the notification prevail.
What this section says, in plain language
Showing an invention in public normally destroys its novelty. A working prototype on a stand, a demonstration to visitors, a printed brochure describing how the device works, all of it can be cited later as prior art. Section 31 carves out a limited exception so that inventors are not punished for taking part in recognised exhibitions or for reading a technical paper before a scholarly body.
Four situations are covered. The first is display of the invention, or of an article made with it, at an industrial or other exhibition that the Central Government has notified in the Official Gazette for this purpose. The second is use of the invention at that place and for the purposes of the exhibition. The third is use of the invention by another person after the display, if that use was without the consent of the inventor or applicant. The fourth is description of the invention in a paper read by the true and first inventor before a learned society, or published with the inventor's consent in the transactions of such a society.
Everything depends on one condition. The patent application must be made within twelve months. That period runs from the opening of the exhibition, or from the reading or publication of the paper. Miss it and the display or the paper becomes ordinary prior art against your own application.
The point most often missed is the word notified. The exception applies to exhibitions the Central Government has notified in the Official Gazette, not to every trade fair, expo, demo day or startup showcase. Before relying on section 31, check whether a notification exists for that specific event. Similarly, a learned society means a scholarly body; a webinar, an accelerator pitch session or a preprint upload is not the same thing, and the paper must be read by the true and first inventor.
Finally, section 31 is an Indian rule and it only answers Indian objections. Many countries either have no grace period or have a shorter and differently worded one. A display that section 31 forgives in India can still defeat the same invention in Europe or China. Treat the section as a rescue, not as a filing strategy.
Why this section matters
Inventors, university researchers, student teams and MSMEs who exhibit prototypes at notified exhibitions or present technical papers before scholarly societies.
It matters from the day the exhibition opens or the paper is read, and it decides whether a filing made months later is still in time.
It creates a limited, time-bound exclusion of the display or paper from the prior art, provided the application is filed within twelve months.
Your own display or paper becomes the citation that destroys novelty, and the invention can be refused during examination or revoked after grant.
How it works in practice
A prototype shown at a notified exhibition
Ananya Rao, a research scholar at IIT Kanpur, builds a hand-held soil nutrient tester that gives readings in ninety seconds. Her institute enters it in a national industrial exhibition that the Central Government has notified in the Official Gazette. The exhibition opens on 12 February and she demonstrates the tester on the stand for four days. Visitors photograph the device and a trade magazine describes it. Working with the institute's technology transfer office, she files a complete specification in India on 9 January of the following year, within twelve months of the opening date. When an examiner later cites the trade magazine article, she relies on section 31, produces the Gazette notification, the exhibition entry documents and the opening date, and the citation is answered. She also learns a hard lesson at the same time. Her European counterpart application, filed on the same day, faces the same magazine article with no equivalent relief available.
Simplified illustration only. Actual legal outcomes depend on the facts.
Key points to remember
- The exhibition must be one that the Central Government has notified in the Official Gazette for this purpose.
- The application must be filed within twelve months of the opening of the exhibition or of the reading or publication of the paper.
- Use of the invention at the exhibition, and unauthorised use by others after the display, are also covered.
- A paper is protected only if it was read by the true and first inventor before a learned society, or published with consent in its transactions.
- The relief operates in India only, and many foreign systems will still treat the display as novelty destroying.
Common mistakes and misunderstandings
- Assuming every trade fair or startup expo qualifies. Without a Gazette notification for that event, the display is an ordinary public disclosure.
- Treating twelve months as a general grace period for any public disclosure. It applies only to the specific situations listed in section 31.
- Filing in India within the twelve months and assuming foreign rights are safe. Foreign filings usually have to be timed from a valid priority filing made before the display.
Connected provisions
- ActSection 29Anticipation by previous publication
- ActSection 32Anticipation by public working
- ActSection 34No anticipation if circumstances are only as described in sections 29, 30, 31 and 32
- ActSection 13Search for anticipation by previous publication and by prior claim
- ActSection 64Revocation of patents
The Patents Act sets the requirement; the Patents Rules, 2003 set the procedure that carries it out. Parliament passes the Act and the Central Government makes the Rules, so the two are separate instruments. We list the connected rules here to take you from the principle to the paperwork.
Forms, deadlines and fees
- The application must be filed within twelve months of the opening of the notified exhibition.
- For a learned society paper, the twelve months run from the reading of the paper or from its publication in the society's transactions.
Open the deadline calculator — and have every date confirmed against the current Rules before you rely on it.
Any official fee connected with this provision is fixed by the First Schedule to the Patents Rules, not by the provision itself. The amount depends on who the applicant is and on whether the filing is made online or on paper, so no figures are reproduced here. How Indian patent fees work.
Amendment history
What changed in this provision, newest first. Read the footnotes in the official consolidated text for the full record.
- 2005The Patents (Amendment) Act, 2005The period within which an application may be filed after a display at an exhibition, or a publication of the description, was extended.
Compiled from official consolidated texts and Gazette notifications. See the site-wide change log.
Related judgments
You will not find case summaries under this heading today. Each one must pass a legal review before it appears, and that work has not been completed for this provision. If you are researching decided cases, use a law report or a court database in the meantime. How case notes are prepared.
Questions people ask about Section 31
How do I know if an exhibition is notified under section 31?
The Central Government notifies specific exhibitions in the Official Gazette, and the notification names the event and the period it covers. Organisers of large national exhibitions often mention this in their exhibitor documents, but you should not take that on trust. Ask the organiser for the notification reference and verify it before you display anything you intend to patent. If no notification exists for the event, section 31 does not apply and the display should be treated as a public disclosure that ends novelty.
Is a conference presentation or a journal paper covered?
Only in a narrow case. The section speaks of a paper read by the true and first inventor before a learned society, or published with the inventor's consent in the transactions of that society. An ordinary industry conference, a webinar, a preprint server upload or a general journal article is not automatically covered. Even where it is covered, the twelve-month clock starts running and the application must be filed inside that period. The safer route is always to file before presenting.
Does section 31 protect me if a visitor copies my exhibited invention?
The section does cover use of the invention by another person after the display where that use was without the consent of the inventor or applicant, so that unauthorised use is not treated as anticipation. That is useful, but it is limited. It does not stop the copying itself, it does not give you rights before you file, and it does not help outside India. The twelve-month condition still applies, so filing quickly after the exhibition remains the practical answer.
Can I use section 31 if I already sold units at the exhibition?
Selling is different from displaying. The section is directed at display of the invention or an article embodying it, use for the purposes of the exhibition, and descriptions arising from the display. Commercial sales are ordinarily a working of the invention rather than an exhibition display, and the exception cannot be assumed to stretch that far. If sales have taken place, the position needs to be assessed on the actual facts and dates before any application is filed.
Did you exhibit or present before filing?
MYCrave Consultancy checks whether the exhibition was notified, works out your twelve-month position and gets the application filed in time.
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