Patent Opposition in India can arise before the grant of patent (Pre-grant opposition) or after the grant of patent (Post grant Opposition).
The main grounds on which a patent is opposed are
Lack of novelty
Wrongful obtainment of patent
Obviousness
Non-patentable subject matter
Anticipation with regard to the knowledge within any local or indigenous community
Pre-grant Opposition can be filed after the publication of a Patent application in the journal brought out the Patent office periodically. The Patent opposition can be filed by any person in writing against the grant of a patent.
The opposition must be filed at the appropriate office together with a statement and evidence in support of the opposition. Subsequently, if the Controller of Patents decides that the application needs amendment or rejection, a notice would be sent to the applicant to which he must reply within a month. The applicant may also request for a hearing. The case is ordinarily decided within a month on completion of the above proceedings.
Post grant Patent opposition can be filed by any person within 12 months from the date of publication of the grant of patent in the Patent office journal.
The notice for Patent opposition is given in the prescribed form at the appropriate office along with a written statement setting out the nature of the opponent's interest, the facts upon which the opponent bases his case, the relief which the opponent seeks, and the evidences. A copy of the statement and evidences is to be provided to the patentee.
In response to the notice of opposition, the patentee should submit a reply statement setting out fully the grounds upon which the opposition is contested and evidence, in support of his case. The patentee has to reply within 2 months from the date of receipt of the copy of the written statement and opponent's evidence by him. The patentee has to deliver a copy of his statement and evidences to the opponent.
The opponent has to reply within 1 month from the date of delivery to him of a copy of the patentee's reply statement and evidence. The opponent has to provide a copy of reply evidence to the patentee.
On the completion of the presentation of evidence, and on receiving the recommendation of Opposition Board, a date and time for the hearing of the opposition may be fixed, which shall be notified to the parties at least 10 days in advance. The party who desires to be heard has to inform the Controller by a notice along with the prescribed fee.
After hearing the party or parties desirous of being heard, and after taking into consideration the recommendation of Opposition Board, the opposition shall be decided and the decision shall be notified to the parties giving reasons for the same.
On receipt of notice of opposition, the Controller constitutes an Opposition Board consisting of three members and nominates one of the members as the Chairman of Board. The Examiner who has dealt with the application for patent during the proceeding for grant of patent is not eligible as a member of the Opposition Board. The Opposition Board conducts the examination of the notice of opposition along with documents (statements and evidences) filed, and submits a report with reasons on each ground taken in the notice of opposition with its joint recommendation within 3 months from the date on which the documents were forwarded to them.