What do you mean by patent opposition?
Patent opposition is either a pre grant opposition or a post grant opposition. In other words, an opposition for a patent can be filed either before the grant of a patent or after the grant of a patent. A pre grant opposition can be filed by any person, by way of a written representation. However, a post grant opposition maybe filed only by any person interested, by giving a notice of opposition to the controller general of patents in the prescribed manner. The ‘person interested’ includes a person engaged in, or in promoting, research in the same field as that to which the invention relates.