How do I file a patent for an invention in India?

Filing runs from search to grant across several years. Pre-filing starts with a novelty search — free at ipindia.gov.in 'Public Search' and internationally on Google Patents, PatentScope (WIPO) and Espacenet — to assess whether your invention is genuinely new. Then draft the specification: title, field, background, summary, detailed description with embodiments, claims (the most critical piece — they define scope of protection), abstract and drawings.

You can file either a provisional application (describes the invention without claims, at lower cost, and secures the priority date, with the complete application to follow within 12 months) or a complete application (full disclosure plus claims). Filing is done online at ipindia.gov.in using Form 1 (application), Form 2 (provisional or complete specification), Form 3 (foreign applications declaration), Form 5 (inventorship declaration), and Form 26 (power of attorney) if filed through an agent.

Fees for individuals, startups and small entities are ₹1,600 for filing and ₹4,000 for examination; large entities pay ₹8,000 and ₹20,000 respectively, with additional fees for specifications above 30 sheets. The priority date — the filing date — anchors novelty determination. Applications are automatically published at 18 months from the priority date, or earlier if you file Form 9.

You must file the Request for Examination (Form 18) within 48 months of priority — otherwise the application is abandoned. The examiner reviews novelty and inventive step and issues a First Examination Report (FER) after 4-30 months. You respond within 6 months (extendable by 3), with amendments to claims if needed, and a hearing may follow. After objections are cleared, the grant certificate issues; refusals are appealable (jurisdiction now lies with the High Court since IPAB was abolished). Total time to grant is typically 3-5 years, with expedited examination available. Renewal fees start from the third year — ₹800 (small) / ₹4,000 (large) for years 3-6 and rising thereafter; a missed renewal ends the patent.

Patentable in India: new products with a technical effect, new processes or methods of manufacture, compositions of matter (chemical, biological), improvements on existing inventions, pharmaceutical inventions (subject to Section 3(d) scrutiny), biotech microorganisms and genetically modified products, and hardware-implemented software (in narrow circumstances).

Not patentable under Section 3 of the Patents Act: scientific discoveries (e.g. gravity), methods of medical treatment, surgery or diagnosis on humans or animals, plants and animals other than microorganisms (varieties are protected under the PVPFR Act), mere admixtures, new forms of known substances without significantly enhanced efficacy (Section 3(d)), software 'per se' (Section 3(k) — though software combined with hardware may qualify), mathematical or business methods, mere arrangement of known devices, integrated-circuit topography (separate regime), traditional knowledge, and atomic energy.

Section 3(d) is the pharma bar — a new form of a known substance is not patentable unless it shows 'significantly enhanced therapeutic efficacy'. The Supreme Court upheld this in Novartis v. Union of India, 2013, entrenching the rule against 'evergreening'. On software, Section 3(k) excludes 'computer programmes per se'; combined with hardware or a technical effect the invention becomes patentable, guided by MeitY guidelines and rulings like Telefonaktiebolaget LM Ericsson v. Intex Technologies (Delhi HC 2015) — telecom and AI-related patents are being granted with increasing frequency.

Pharmaceutical patents remain a major Indian battleground because of the strict Section 3(d) screen, the compulsory licensing route under Section 84 (used in Natco v. Bayer for Nexavar) and overarching public health considerations. Standard Essential Patents covering telecom, USB and WiFi standards are enforced through FRAND licensing, and the framework continues to evolve.

Examination is triggered by Form 18 within 48 months of the priority date — miss it and the application is abandoned. The examiner cites prior art and raises objections in the First Examination Report, which typically arrives 4-30 months after the Request for Examination. You respond within 6 months (extendable by 3) with arguments and claim amendments, and a hearing before the examiner is a final opportunity if the response is not accepted. A grant issues if the examiner is satisfied; a refusal is appealable.

Two windows exist to oppose: pre-grant opposition under Section 25(1), open to anyone after publication and before grant on Form 7A, grounded on wrongful obtaining, anticipation, lack of inventive step, non-patentable subject matter, or insufficient disclosure; and post-grant opposition under Section 25(2), open to any interested person within one year of grant on Form 7, examined by the Opposition Board. Beyond opposition, revocation under Section 64 lies before the High Court on the same grounds plus lack of fair basis, fraud, etc.

Compulsory licensing under Section 84 is available three years after grant if the patent is not being worked or reasonable requirements are not being met — the government or a third party may apply. The most cited example is Natco v. Bayer over the anti-cancer drug Nexavar. Patentees must file Form 27 annual working statements disclosing the extent of working.

Adjacent tools: patents of addition (improvements with a concurrent term), divisional applications (when the single inventive concept rule is breached), convention applications claiming priority within 12 months of a foreign filing under the Paris Convention, and PCT national phase entry within 30/31 months of international filing. Expedited examination on Form 18A is available for startups, MSMEs, women applicants and others, and cuts the timeline to roughly 12-18 months. Section 100 allows government use of patented inventions for a public purpose on notice.

Section 48 gives the patentee the exclusive right to make, use, sell and import — anyone doing so without authorisation infringes. A suit for infringement lies in the District Court, Commercial Court or High Court, and reliefs include permanent injunction, damages or account of profits, delivery up and costs. Interim injunctions are common in strong cases. Courts apply three tests: the all-elements rule (every element of the claim in the infringing product), the doctrine of equivalents (substantially same way, similar function, similar result), and the pith and marrow doctrine.

Defences include patent invalidity (typically as a revocation counter-claim), Section 107 exemptions for experimental use and regulatory submissions, prior use, government use, and a compulsory licence. Standard Essential Patents in telecom (3G, 4G, 5G) are enforced under FRAND (Fair, Reasonable, Non-Discriminatory) licensing, with Ericsson v. Intex, Ericsson v. Lava and Nokia v. OPPO shaping Indian doctrine on royalty determination and cross-licensing. Customs enforcement runs through IPR Recordal that lets Customs detain infringing imports. Patent infringement is primarily civil, though some falsification offences are criminal.

Damages may be calculated as lost profits, reasonable royalty, or an account of the infringer's profits, with punitive damages in egregious cases. Landmarks: Novartis v. Union of India (2013) upheld Section 3(d); Bayer v. Natco (2014) applied compulsory licensing; the Ericsson SEP line built out the FRAND framework.

Patent litigation is expensive — lawyer fees ₹5-50 lakh plus, expert evidence ₹2-20 lakh, and heavy technical demands. Most disputes settle, with cross-licensing and royalty arrangements common between major players, and patent pools organising the field in some sectors. For international protection, the PCT route provides a single application across ~150 member countries with local agents needed in each, and the Paris Convention preserves priority for 12 months. Patents can be monetised through licensing (passive or active), used as strategic deterrents, sold or transferred, offered as loan collateral, and factored into M&A valuation and IPO disclosures.

Several schemes tilt the economics for smaller inventors and specific fields. Startup India / DPIIT recognition gives an 80% rebate on patent filing fees, expedited examination, and free legal assistance through empanelled facilitators — grants typically land in 12-18 months. MSMEs get similar rebates and access to Patent Information Service Centres. Specific programmes include NIDHI (Department of Science and Technology), SIP-EIT (MeitY, up to ₹15 lakh support for international patents in Electronics and IT), TIDE (MeitY), and various state schemes in Karnataka (KITS), Tamil Nadu (TIDCO), Maharashtra and Telangana. Educational institutions — IITs, IISc, NITs — run technology transfer offices offering filing support, and the Atal Innovation Mission under NITI Aayog operates incubation centres, AICs and ATL labs.

Filings by anyone other than the inventor or applicant require a qualified patent agent — an engineering or science degree plus the qualifying exam — and complex applications almost always benefit from one. Free legal aid is available through DLSA and pro bono patent agents via industry bodies, and the Indian National Institute of Intellectual Property Management (WIPO India) runs training and awareness.

Common inventor mistakes: public disclosure before filing (which destroys novelty), filing without a search, vague or overbroad claims, insufficient disclosure, missing the PCT timeline for international protection, letting renewals lapse, and filing without proper representation. Better mindset: file before disclosing, use a provisional as a safety net, consider trade secret protection where the invention isn't independently discoverable, and use defensive publication for non-strategic inventions.

Patent vs trade secret: a patent gives 20-year protection in exchange for disclosure; a trade secret is indefinite while maintained. Prefer a patent if the invention is discoverable through reverse engineering; prefer a trade secret for processes that are hard to reverse-engineer. Pharma startups face strict Section 3(d) screening, must think through new chemical entities vs new forms, and can rely on clinical data exclusivity and regulatory data protection. Software startups operate under Section 3(k)'s limits and the technical effect requirement, with copyright covering code and trade secret covering algorithms. Engage a specialised patent attorney or agent — for valuable inventions the investment pays back many times over.