In this article, Kanishka Chakrabarti who is currently pursuing M.A. IN BUSINESS LAWS, from NUJS, Kolkata, discusses Post-grant opposition and revocation proceedings under the Indian Patent Act.


  • Patent is a right that is exclusive which is granted to the original inventor for an innovative product or a novel process that provides a unique way of doing something or that which provides for a novel technical resolution to a problem. It provides an exclusive right to the inventor to manufacture, sell his invention or product. Therefore it is very crucial that a patent is only bestowed to those inventions which validate the exclusive right and comply with the criteria stated above.
  • A patent, once granted, does not imply that the same will stay unchallenged by any party during its life. In spite of the granting of a patent, it can be put to trial by certain persons on various grounds, either through a post-grant opposition or by way of revocation proceedings.

Opposition to Patent

There are provisions under the Indian Patent Act pertaining to oppositions. They are put in place to ensure that unfair obtaining of patents and claiming inventions which are trivial or insignificant are prohibited.

An opposition proceeding can be termed as an administrative process under the authority of the Patent office which permits a party to challenge a patent.

  • Oppositions can be filed at various stages which is contingent upon the phase of the patent, either at the pre-grant stage (in order to obstruct unlawful grant of patent) or at the post-grant stage. Thus, oppositions are of two types under the Act, pre-grant oppositions, and post-grant oppositions.
  • India signed the Trade Related aspects of Intellectual Property Rights (TRIPS) Agreement on 1st January, 2005. Subsequently Section 25 of the Act was amended to adhere to the agreed terms of TRIPS, which provides for an integrated system of pre and post grant oppositions.
  • As the scope of this project is restricted to post grant oppositions and revocation proceedings, we will be concentrating on these aspects and will not be discussing the pre-grant opposition in elaborate detail.

Post Grant Opposition

  • A Post grant opposition can be raised after a patent is granted, provided that such opposition is filed before the expiry of 1 year from the date of publication of allowance of the patent.
  • As per the Act, any ‘person interested[1]’ and wishing to oppose a patent, can file a notice of opposition addressed to the Controller ensuring that the notice fulfills the criteria provided under Section 25 of the Patents Act, 1970. The ‘person interested’ definition provided under the Indian Patent Act includes a person who is engaged in, or in promoting, research in the same field as that to which the patent relates. An ‘interested person’ also includes any organization that has manufacturing/trading/financial interest in products that relate to the product that has been patented.

Post grant oppositions can be filed on the basis of a number of reasons as stated in Section 25 (2) of the Patents Act.

It is to be noted that a number of conditions under which a patent can be opposed post-grant are similar to the reasons provided under section(s) related to revocation proceedings.

The grounds are as stated hereunder:

  • Invention was publicly known or practiced prior to the claim of priority date.
  • The invention has been published or filed prior to the filing of the applicant
  • Invention on which claim is made has been published before.
  • Applicant obtains the patent through wrongful means.
  • Invention is obvious and is devoid of any novel step.
  • The ‘invention’ does not amount to an invention as contemplated under the act, or is not patentable.
  • The specifications do not adequately describe the invention or the means through which the same can be performed.
  • Failure to disclose to the Controller the information required under Section 8, or has done so fraudulently.
  • Convention patent application has not been filed within one year of filing the first application in a convention country.
  • Specifications do not, or wrongly reveals source of biological material utilized in the invention.
  • Invention was foreseen in light of knowledge available within any local or native community in India or elsewhere.

Important differences between Pre-Grant Patent Opposition & Post-Grant Patent Opposition

It is to be noted that even though one had opposed a patent at the pre-grant stage, nothing prevents him from filing an opposition at the Post-grant stage.

Pre-Grant Opposition Post-grant Opposition
Can be filed by any person. Can be filed by only ‘person interested’.
Infringement cannot be alleged as the patent has not been granted. As patent has already been granted, infringement proceedings can be started.
Does not explicitly give the Patent Applicant a right to hearing. Provides the Patent Applicant an opportunity to be heard.
Does not directly allow the party opposing a right to be heard. A request has to be made for the same and the rules do not provide for how the hearing is to be conducted. The discretion of providing the opponent an opportunity lies with the Patent Controller, who may or may not provide the same based on what he feels are the merits of the opposition. The Opponent’s right to be heard is irrespective of the merit of the opposition.
No fees required for filing opposition. Fees required to file opposition (Rs. 1500 in case of natural person and Rs. 6000 in case of any person other than a natural person) and overall a costly process.
The process is faster. Process is lengthier owing to hearings, and by extension thereof delays, extensions etc.
Decision can only be challenged by way of a writ petition. The Controller’s decision is open to challenge by way of appeal to IPAB.

  • On granting of a patent and before the expiration of a 1 year period from the date of publication of grant of patent, any ‘person interested’ can file a notice of opposition to the Controller. In the event that the patentee wishes to challenge the opposition, he shall submit a counter-reply statement at the office concerned, detailing the reasons and grounds on the basis of which he believes that the opposition should be dismissed. He can also furnish evidence in support of the same. Further, the opponent in turn can file counter-evidence or reply, the scope of which is to be limited to the patentee’s reply.
  • The Controller thereafter shall form an Opposition Board (consisting of three members) which will carry out a detailed scrutiny and investigation of the patent and submit their findings and recommendations to the Controller within three months of receipt of relevant documents.
  • The Controller shall fix a date of hearing and intimate the same to the patentee and opponent.
  • On the date of the hearing, the parties are to present their respective arguments, and the Controller shall, on the basis of the arguments and the findings of the oppositions board decide the matter.
  • The controller shall convey his decision to the parties and provide the reasons on the basis of which he arrived at the same.

The Supreme Court, in the case of Cipla Ltd. vs. Union of India & Ors.[2], has laid stress on the principles of natural justice during the opposition process as well as the importance of the recommendations of the Opposition Board. The Supreme Court has opined that the Opposition Board’s recommendations must be made available to the parties concerned in order for the parties to effectively argue their contentions before the Controller at the time of hearing. The Court has stated that even though the Act and the Rules do not mandate the Controller or the Opposition Board to provide copies of the recommendation to the parties, as the report is a crucial document in the decision making process, the principles of natural justice should prevail.

Revocation Proceedings

  • All persons (except patentee) are required to seek permission from the patentee for utilizing any of the exclusive rights conferred to the patentee. However, this does not mean that such parties cannot challenge the validity of the patent concerned. Apart from post-grant opposition, revocation is another option that lies with ‘person interested’ (among others) to question the legality of a patent.
  • Under Section 64 of the Indian Patents Act, a patent may thus be revoked on, (i) petition of a person who is the person interested or petition of the Central Government or (ii) a counter claim in a suit for infringement of patent.
  • It is to be noted that the forum would differ in the above cases, for any person interested or the central government the petition would lie before the Intellectual Property Appellate Board, and in case of the person making counter-claim in a suit for the revocation of the patent concerned, it would have to be before the High Court.[3]

Conditions under which Revocation Proceedings can be initiated

  • An invention with same complete specifications has already been claimed, and has been granted patent.
  • The patent was granted to a person who was not entitled to apply for the same.
  • Patent was wrongfully obtained in violation of rights of another party/petitioner/person through which patent has been claimed.
  • Subject of the claim does not amount to invention.
  • Invention claimed is not new; is publicly known, publicly used in India before the priority date or was published in India or elsewhere in the documents referred in Section 13 of the act.
  • Invention is obvious or lacks any inventive step.
  • Invention is not of any use.
  • The specifications are inadequate, so far as describing the invention or method of usage is concerned.
  • Scope of claim or complete specification is not clearly defined.
  • Patent obtained through incorrect or false proposal or representation.
  • Subject of the claim is not patentable under the purview of the Patents Act.
  • Invention claimed was secretly used in India before the date of claim.
  • Applicant has not been able to disclose information required under section 8 or has furnished information was known by him to be false.
  • Applicant has contravened direction for secrecy under Section 35.
  • Leave to modify specification under Section 57 or Section 58 was obtained through fraudulent means.
  • Complete specification doesn’t state, or states erroneously the source or geographical origin of biological material used in the invention.
  • Invention claimed was foreseen in light of the knowledge available within any local or native community in India or elsewhere.

However, it should be noted that the grounds laid down in Section 64 (1) of the Indian Patents Act is not exhaustive.

Further, Section 65 provides that the Central Government may revoke a patent after ascertaining that the invention relates to atomic energy and no patent on the same can be granted as per the relevant provisions of the Atomic Energy Act, 1962.

Also, under Section 66, if the Central Government deems that a patent or the manner in which the rights to the same are being exercised is detrimental to the interests of the public or the state, then such patent can be revoked, albeit an opportunity to the patentee is to be given, with respect to his right to be heard.

Under Section 85 of the Patents Act, a person interested or the Central Government may apply to the Controller for revoking a patent with respect to which compulsory license had been granted, if within two years of its grant,

  1. if it has not worked in the territory of India, or
  2. the public’s reasonable requirement from such patent has not been fulfilled, or the invention has not been made available to the people-at-large at a reasonable level of affordable pricing.

Instance of Revocation under Section 66

  • Avesthagen Ltd. had been granted a patent on a product consisting of Jamun, Lavangpatti and Chandan which was proposed to be used for treatment of diabetes. Avesthagen’s filing for patent in the said product in the European Patent Office (EPO) was turned down under the ground that it infringed upon Traditional Knowledge Digital Library (TKDL).
  • The Central Government of India, on finding out about the same, revoked the patent that was granted to Avesthagen by the Indian Patent Office under Section 66 of the Indian Patents Act, i.e. on the patent being prejudicial to the interests of the public and being mischievous.
  • Avesthagen’s argument that while it was traditional knowledge, but the fact that when used in this particular combination they show an accelerated effect did not hold water, as the Central Government argued and proved that the fact that these plants were used for management of diabetes was known for centuries, and it was obvious that their extracts would perform the same function. Held, a patent cannot be granted for re-validating a traditional knowledge.

Important points of comparison between Post-grant Opposition & Revocation

Scope Post-grant opposition Revocation
Relevant Section 25 (2) 64, 65, 66, 85
Locus Standi Person Interested Person Interested / Central Govt., / Supposed Infringer in a  Counter Claim
Appropriate Forum Patent Office Intellectual Property Appellate Board / High Court
Relevant point of time After the grant of patent but before the expiry of one year from the date of publication of grant of a patent. After grant of patent and during its subsistence.
Reasons Limited to grounds provided under Section 25 (2) Reasons stated under Section 64, 65, 66 and 85 are not exhaustive.



  • It is interesting to observe that criteria to be fulfilled by a challenger in case of post-grant opposition are comparatively stricter than in case of pre-grant opposition. However, subsequently, as compared to post-grant opposition, the criteria applicable for revocation proceedings appear to be relaxed. The proceedings under Section 25 (2) and Section 64 are two different and distinct proceedings. There is nothing in the Act to prevent an unsuccessful party in an opposition proceeding under Section 25 (2) to proceed under Section 64 for revoking the patent.
  • The two-tier opposition process combined with the revocation proceedings has proved to be overwhelming for genuine innovators, more so in the pharmaceutical industry. As a pharma giant and one of the fastest growing economies in the 21st century, India is struggling to balance adherence to TRIPS, multiplicity of suits and looking after interests of the general public.
  • Oppositions as a mean of invalidating patents find favour particularly owing to lesser expenses and quick resolution as opposed to revocation proceedings, which generally is a much more long drawn process. As stated above, pharmaceutical companies in particular file a large number of oppositions, but lately other industries too have started to sit up and take notice of the advantages of filing oppositions to nip in the bud susceptible patents.

Popular grounds under which most oppositions are filed are ‘novelty’ and ‘inventive step’. Lately, procedural grounds are also being alleged as a key factor for denying patents. [4]

The Delhi High Court, in the Chemtura Case[5] stated that the requirement of updating the Controller about the status does not equate to merely stating the countries of filing or the status whether it is “pending or dismissed”. Further, the requirement is not fulfilled by informing once regarding filing of similar applications outside the country; rather the obligation is a continuing one to inform the Controller about any changes in the status from time to time.

The Supreme Court has clarified in its judgement in the case of Dr. Aloys Wobben & Anr. Vs. Yogesh Mehra & Ors.[6] that as per Section 64 of the Patents Act, revocation can be sought by either a counter claim in suit for infringement OR by filing a revocation petition before the IPAB, the challenger cannot attempt to simultaneously proceed against the patentee in both the matters. Attempting to seek one of the remedies would bar him from availing the other.

The Supreme Court, aware that multiplicity of suits was often a tool for cash-rich litigants with less than honest interests formulated guidelines, viz.

  1. If an infringement suit has been filed and a counter-claim for revocation is made, it is the High Court that would decide upon revocation. The defendant in the suit for infringement is barred from filing a revocation petition with the IPAB (so far as it deals with the same matter).
  2. Similarly, as a corollary, if a revocation petition is filed with the IPAB against a patent, and a suit for infringement is filed pertaining to the same patent, the defendant in the suit was disentitled from seeking revocation of patent while filing his counter-claim. The revocation petition with the IPAB would be decided.[7]

Differing standards of obviousness?

  • ‘Obviousness’ or ‘lack of inventive step’ is a common element that finds a place as a basis of rejection of patent in both opposition and revocation. However, on closer inspection of the provisions relating to them respectively, it can be noted that the word “clearly” finds a place in Section 25 (1) (e) and 25 (2) (e) [pertaining to pre-grant and post-grant opposition respectively] but not Section 64 (1) (f), i.e. relating to revocation proceedings.
  • This implies that while the person opposing in post grant opposition before the Controller needs to establish without doubt the lack of an ‘inventive step’ but while appearing in front of the IPAB (or High Court) the same extent of ‘proof’ need not be the case.
  • The question of whether an inventive step is involved is both a question of law and a question of fact and while the Controller need not necessarily possess a legal background, the same is not the case with IPAB (one member required to have legal background)& the High Court.  Perhaps it is owing to this fact that the intention of the legislature was such that the Controller need not refuse/strike down a patent unless he is fairly certain that there was no inventive step involved, with respect to the IPAB/High Court, it is assumed that the rationale will be explained and heard to a greater degree than in front of the Controller.

Therefore, it can be concluded that a challenger who files an opposition citing lack of an inventive step, requires a higher degree of proof, in order for him to successful, as opposed to revocation proceedings.

As a corollary, in case of revocation proceedings, the court should not issue a decision in favour of the patentee based on giving benefit of doubt.

[1]Section 2 (1) (t) of the Indian Patents Act.

[2] SC, Civil Appeal No(s).8479-8480 of 2012

[3]Section 104 of the Patents Act provides that no suit for infringement can be brought before a court lower than a District Court having jurisdiction to try the matter, and in case of a counter claim for revocation made by the defendant, the same must be transferred  to the High Court.


[5] Chemtura Coporation vs. Union of India & Ors. In the High Court of Delhi, CS (OS) No. 930 of 2009.

[6] Civil Appeal No. 6718 of 2013 decided on June 2, 2014 (Citation presently unavailable).


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