The scheme of the Indian Patents Act allows a patent application or patent to be opposed at two levels before the patent office: first at the pre-grant stage by "Any person" and second at the post-grant stage by "Any person interested".
Section 25 (1) of the Patent Act allows "Any person" to file a pre-grant opposition. The intent of the legislature to introduce said provision by amendment in 2005 was to assist the patent office during examination of the patent application. Read more