Delhi HC holds that IPO must identify”Known Substance” for raising objections under Sec 3(d)November 17, 2022IPO section 3d, IPO section 3d objection, patent 3d objection, Patent 3d rejection, Patent objections 3D, replying 3d rejection, section 3d Indian patent actBlogph13030083162_kj63e10j Patent Office should identify Known Substance for raising Sec 3(d) objections – Delhi High Court