Navigating the Patent Filing Process: From Ordinary to PCT National Phase Applications

Filing a patent in India is not a single, one-size-fits-all process. Depending on where your invention originates, whether you have prior filings in other countries, and how broadly you want to protect your innovation, the route you take – and the documents you prepare – can differ significantly. The Patents Act, 1970 and the Patents Rules, 2003 (as amended) together govern this process, recognising three primary filing routes: ordinary applications, convention applications, and PCT national phase applications. Understanding each of these is essential for any inventor who wants to protect their work effectively in India.

The ordinary application: India’s default filing route 🔗

An ordinary application is the most straightforward path. It is filed directly with the Indian Patent Office (IPO) without claiming any priority from an earlier application filed anywhere else. This is typically the route domestic inventors take when they are filing for the first time and have no prior international applications to rely on.

Who can file 🔗

Under Section 6 of the Patents Act, 1970, the following persons are entitled to apply for a patent: the true and first inventor, the assignee of such inventor, or the legal representative of a deceased inventor or assignee. Importantly, every application must be for a single invention or a group of inventions linked by a single inventive concept – this is the unity of invention requirement under Section 10(5).

Documents required 🔗

To file an ordinary application, an inventor needs to submit the following to the IPO:

• Form 1 – Application for grant of patent. This is the primary application form and must include a declaration as to inventorship.
• Form 2 – Specification of the invention, which can be either provisional or complete.
• Form 3 – Statement and undertaking under Section 8 of the Act, disclosing details of corresponding patent applications filed outside India, if any.
• Form 5 – Declaration of inventorship, required when a provisional specification is later followed by a complete specification.
• Form 26 – Power of attorney, if the application is being filed through a registered patent agent.
• Form 28 – Required if the applicant is a startup or small entity seeking the concessional fee (which can amount to an 80% reduction in official government fees).

These forms are available on the official IPO portal, where the application can also be filed electronically in PDF format.

Provisional vs. complete specification 🔗

One distinctive feature of Indian patent law is the option to file a provisional specification at the outset. A provisional specification gives an inventor the benefit of an early priority date without requiring fully developed claims – useful when the invention is still being refined. However, a complete specification (which must include full technical details, claims, and an abstract) must then be filed within 12 months. If this deadline is missed, the application is deemed abandoned under Section 9(1) of the Patents Act.

It is worth noting that a provisional specification cannot be filed in the case of convention applications or PCT national phase applications – a complete specification is mandatory from the outset in those routes.

Convention application: protecting your foreign priority in India 🔗

If an inventor has already filed a patent application in a country that is a member of the Paris Convention for the Protection of Industrial Property, they may file a corresponding application in India while claiming the date of that earlier filing as their priority date. This is called a convention application and is governed by Section 135 of the Patents Act, 1970.

The 12-month window 🔗

A convention application must be filed in India within 12 months from the date of the first filing in the convention country. This is a strict deadline – missing it means losing the right to claim priority from that earlier application. The priority date matters because it determines which prior art can be cited against the invention during examination.

Additional documents required 🔗

In addition to all the forms required for an ordinary application (Forms 1, 2, 3, 5, 26, and 28 where applicable), a convention application requires the following additional documents:

• Certified priority document – A copy of the application filed in the first convention country, certified by that country’s patent office as a true copy.
• Verified English translation – If the priority document is in a language other than English, a verified English translation must be submitted.

The priority document must typically be submitted within 3 months from the date of filing the application in India. This period can be extended by one month by filing Form 4 along with the prescribed fee. It is also important that the applicant in India can be a different entity from the applicant in the convention country, provided the appropriate assignment documentation is in place.

PCT national phase application: the global filing route entering India 🔗

The Patent Cooperation Treaty (PCT), administered by the World Intellectual Property Organization (WIPO), allows inventors to file a single “international” patent application designating multiple countries simultaneously. India became a contracting state to the PCT on December 7, 1998, and the PCT system has since transformed how international applicants seek protection in India. In 2024, India ranked 6th globally in patent filings, a milestone directly connected to its participation in this treaty.

The two phases of PCT 🔗

The PCT process has two distinct stages. The international phase involves filing a single international application at WIPO or a receiving office, undergoing an international search by an International Searching Authority (ISA), and receiving a written opinion on patentability. The national phase then follows, where the applicant must enter individual countries – in this case, India – by complying with Indian-specific requirements under the Patents Act.

The 31-month deadline 🔗

A PCT application must enter the Indian national phase within 31 months from the earliest priority date. This is a critical deadline. If missed, the application is treated as withdrawn in India and there is no general restoration mechanism. Under the Patents (Amendment) Rules, 2024, effective March 15, 2024, the deadline to file the Request for Examination (Form 18) has also been brought in line with this 31-month window for applications filed on or after that date. This means applicants must now plan to file both the national phase entry and Form 18 simultaneously – a significant procedural change from the earlier 48-month examination window.

An extension of up to 6 months beyond the 31-month deadline is available, but this requires payment of additional fees and should not be relied upon as a matter of routine.

Documents required for PCT national phase entry 🔗

The documents needed for entering the Indian national phase are as follows:

• Form 1 – Application for grant of patent. The details in this form must correspond exactly with the information publicly available on WIPO’s records on the date of filing. No amendments to the applicant’s or inventor’s name or address are permitted at the time of national phase entry.
• Complete specification (Form 2) – A provisional specification cannot be filed for PCT national phase applications.
• Form 3 – Statement of foreign applications, including information about family patent applications (application numbers, filing dates, publication details). This must be filed at the time of filing or within 3 months of filing.
• Form 5 – Declaration of inventorship.
• Form 18 – Request for examination, now required within the 31-month window for applications filed after March 15, 2024.
• Proof of right (signed Form 1 or assignment deed) – This can be submitted at the time of filing or within 6 months from the filing date.
• Power of attorney (Form 26) – Foreign applicants must engage a registered Indian patent agent, as they are required to have an address for service in India.
• English translation – If the PCT specification as filed or published at WIPO is in a language other than English, a verified English translation must be submitted within the 31-month deadline.

Key restrictions unique to India 🔗

India’s national phase procedures have a few important distinctions that applicants must keep in mind. Unlike most jurisdictions, the Indian Patent Office does not allow any amendments at the time of national phase entry. Any changes to claims, specifications, or applicant details that were made during the international phase but not yet publicly reflected on WIPO’s database cannot be incorporated into the Indian national phase application at the point of filing. Only amendments that are publicly available on WIPO’s records on the filing date can be reflected. Post-entry amendments are possible but come with limitations.

Common post-filing steps across all application types 🔗

Regardless of which type of application is filed, all patent applications in India must go through the same downstream procedures before a patent is granted:

• Publication – Under Section 11A of the Patents Act, applications are published in the Official Journal of the Patent Office 18 months from the filing or priority date, whichever is earlier. An early publication request can be made using Form 9, which triggers publication within one month of the request.
• Request for examination – Filing Form 18 is mandatory to initiate substantive examination. Without it, the application is considered withdrawn. For ordinary and convention applications, the deadline is 48 months from the filing or priority date; for PCT national phase applications filed after March 15, 2024, it is now 31 months.
• First Examination Report (FER) – The patent office may raise objections through the FER, and the applicant has 6 months to respond (extendable by 3 months via Form 4).
• Grant – If all objections are resolved and requirements are met, the patent is granted and entered in the register.

A quick comparison of the three routes 🔗

Here is a side-by-side summary of the key differences:

• Ordinary application: No prior filing required; provisional or complete specification; no priority deadline constraint; Form 5 not mandatory at filing.
• Convention application: Must be filed within 12 months of first foreign filing; complete specification mandatory; certified priority document required within 3 months.
• PCT national phase: Must enter within 31 months; complete specification mandatory; Form 18 must now be filed within the same 31-month window (for filings post-March 15, 2024); no amendments permitted at the time of entry; foreign applicants must use a registered Indian patent agent.

Each route exists to serve a different kind of inventor – the domestic startup taking its first steps, the company hedging its bets internationally through the Paris Convention, or the global enterprise using the PCT to defer country-specific decisions while keeping options open. Knowing which route applies to your situation, and getting the documentation right from the outset, can mean the difference between a successfully granted patent and a procedural misstep that costs years of effort.

What do you think? If you were an Indian startup that had developed an invention and wanted to file in both India and the United States simultaneously, which filing route would serve you better – the Paris Convention route or the PCT route – and what factors would influence that choice? Also, given that India does not allow amendments at the time of PCT national phase entry, how should applicants prepare their international application to account for this constraint from the very beginning?

References

1. https://www.indiacode.nic.in/handle/123456789/1392
2. https://ipindia.gov.in/writereaddata/Portal/ev/rules-index.html
3. https://ipindia.gov.in/
4. https://www.intellectbastion.com/a-researchers-checklist-documents-required-for-patent-filing-in-india/
5. https://www.wipo.int/treaties/en/ip/paris/
6. https://ssrana.in/ip-laws/patents/patent-application-filing-india/
7. https://www.wipo.int/pct/en/faqs/faqs.html
8. https://www.rkdewan.com/blogs/pct-national-phase-india-filing/
9. https://www.intepat.com/blog/pct-patent-india
10. https://www.aipla.org/list/innovate-articles/entering-the-national-phase-of-patent-applications-in-india-under-the-patent-cooperation-treaty
11. https://ip-coster.com/IPGuides/patent-pct-india