After publishing of the patent application it may be opposed or objected on the reasonable grounds. Opposition of patent is necessary to restrain wrongful obtaining of patents and claiming of the frivolous or obvious inventions. Opposition may be of two types- Pre-grant opposition and Post grant opposition.

Following are the grounds of opposition:-

• Wrongfully obtaining the invention
• Anticipation by prior publication
• Obvious invention and does not contain any inventive step
• Anticipation by prior date or prior claiming in India
• Prior public knowledge or public use in India
• Non-disclosure of information as per the requirement or providing materially false information by an applicant
• Patent application not filed within 12 months of filing the first application in a convention country