Delhi HC Patent Decisions Show Tighter Review Under Section 3(i)

Delhi HC Patent Decisions Show Tighter Review Under Section 3(i). Recent decisions of the Delhi High Court reflect a marked shift toward closer judicial review while interpreting Section 3(i) of the Patents Act, 1970, which excludes methods of treatment, diagnosis, and surgical processes from patentability. Rather than relying on a mechanical application of the statutory bar, the Court has increasingly examined the substance and technical contribution of claimed inventions. This nuanced approach distinguishes between impermissible treatment methods and patent-eligible innovations that demonstrate a tangible technical effect, improved efficacy, or a novel industrial application beyond mere medical procedure. Through these rulings, the Delhi High Court has reinforced a balanced patent jurisprudence one that safeguards public health concerns embedded in Section 3(i) while ensuring that genuine technological advancements are not denied protection merely due to their medical context. This evolving judicial stance signals greater clarity for innovators and practitioners and underscores the Court’s role in aligning patent law with contemporary scientific progress and global best practices.
The shift you’re noticing from “deference” to “discipline”
A visible pattern in 2025 patent appeals (especially before the Delhi High Court’s IPD bench) is that the Court is no longer satisfied with Patent Office refusals that merely quote Section 3(i) and conclude: “therefore non-patentable.” Instead, the Court is increasingly insisting on disciplined, claim-focused reasoning and when the reasoning looks conclusory, it either sets the order aside or remands the matter for fresh consideration with proper analysis.
This is not the Court “lowering” the Section 3(i) bar. Section 3(i) remains a strong exclusion. The change is that the Court is saying, if you want to refuse, you must show your work.
 That “show your work” approach appears clearly in the October 9, 2025, batch of decisions interpreting diagnostic-method exclusions under Section 3(i).
Quick refresher: what Section 3(i) excludes (and why it creates disputes)
Section 3(i) excludes from patentability: (i) “any process for the medicinal, surgical, curative, prophylactic, diagnostic, therapeutic or other treatment of human beings,” and (ii) similar treatment of animals to render them free of disease / increase economic value.
On paper, it sounds straightforward, no method-of-treatment patents. In practice, disputes arise because many inventions sit in the grey zone, for example; a composition or kit that is used in treatment (product claims); a diagnostic workflow that uses lab steps and data processing; a “screening” method that might effectively function like “diagnosis”; and inventions where the specification talks about treatment, but the claims are framed as technical steps or products.
So, courts have to repeatedly answer: is the claimed subject matter truly a prohibited “process of treatment/diagnosis,” or is it a patentable technical invention that merely has medical use?
What triggered stricter review in 2025: “conclusory refusals” became a recurring problem
A “conclusory refusal” typically looks like the order describes the invention as treatment/diagnosis (sometimes using the specification’s purpose statements), quotes Section 3(i), and then refuses without mapping each claim element to Section 3(i), explaining how the claim constitutes a “process for treatment/diagnosis,” or addressing the applicant’s amendments/arguments in a structured way.
In other words, the refusal feels like label first, analysis later (or not at all). The Delhi High Court’s 2025 approach pushes back on this and demands, correct characterization of the invention, and a structured chain of reasoning.
You see this strongly in the way the Court frames the issues and then proceeds to analyze Section 3(i) in detail in the 2025 diagnostic-method decisions.
The Court’s method: “characterize first, then apply the exclusion”
A consistent judicial technique in these cases is: Step A: Identify what the claims cover (not merely what the invention is “for”). Courts stress that the scope of the invention must be determined from the claims (read with the specification), not from broad statements like “for treating disease X” or “for diagnosis.”
In the Medilabo v. Controller appeal (C.A.(COMM.IPD-PAT) 16/2024, decided Nov 24, 2025), the dispute itself shows this tension: The applicant argued the claims are composition/kit claims, not treatment methods. The Patent Office position (as recorded) was that the invention is implicitly directed to a dosage regimen/treatment method based on how the specification/examples operate. This is exactly where courts demand careful analysis: Does the claim, as granted/refused, contain treatment steps? Or is it a product claim being refused only because of its eventual medical use?
Step B: Pinpoint the “treatment/diagnostic” element with precision. If the refusal is under Section 3(i), the Controller must identify what part of the claim constitutes a process for treatment/diagnosis, and why that part is not merely an ancillary technical step. In the EMD Millipore matter, the Delhi High Court explicitly frames the interpretive exercise as determining the scope of Section 3(i) for diagnostic methods and whether the subject invention falls within it signaling that Section 3(i) is not applied by label, but by analysis.
Step C: Give a reasoned conclusion (not a summary conclusion)
The Court’s approach effectively imposes a “speaking order” discipline: a] address the applicant’s core arguments, b] deal with amendments, and c] explain why the invention is (or isn’t) excluded.
Diagnostic methods under Section 3(i): why 2025 decisions became a “mini framework”
October 9, 2025, batch (including EMD Millipore and connected prenatal testing appeals such as Sequenom) is important because it treats Section 3(i) diagnostic disputes as a principle-setting question, not just fact disputes.
In Sequenom’s connected appeals, you can see the controversy the Court is dealing with:
Applicant: “This is a screening test, not diagnosis.”
Respondent: relies on statutory definitions under the PCPNDT Act to argue prenatal testing is diagnostic.
The Court heard these in a batch led by EMD Millipore specifically to interpret Section 3(i)’s diagnostic exclusion.
This illustrates the “closer review” pattern, the Court does not accept a simplistic “it’s medical, so excluded.” and it interrogates what counts as “diagnostic” and how “screening vs diagnosis” should be handled in patentability analysis.
This kind of reasoning naturally raises the bar for Patent Office orders: the Controller must show why the claimed method performs diagnosis (or is a diagnostic process), rather than just calling it diagnostic.
“Correct characterization” the heart of the pattern
When courts say “characterization,” they mean: What is the invention, in claim terms?
 Not: what the product is intended for, what the specification markets it as, or what the examiner assumes it does.
This matters because: A composition used in treatment is not automatically a “process for treatment.” A kit used for diagnosis is not automatically a “diagnostic process,” and a method that produces a risk score or screening output may or may not be “diagnosis” depending on how the claims are framed and what the output enables.
The Delhi High Court’s insistence on proper characterization is visible in how disputes are presented in cases like Medilabo where the applicant argues the Controller wrongly treated product claims as method claims and also argues that the Controller improperly relied on claim preamble language (purpose statements) rather than limiting steps.
Why courts are sensitive to “preamble” and “end-use” shortcuts
In many pharmaceutical/medical inventions, claims include phrases like: “A composition for treating Alzheimer’s disease”, “A kit for diagnosing condition Y” and A shortcut refusal often happens when: the Controller treats “for treating/for diagnosing” as automatically converting the claim into a Section 3(i) excluded method.
But courts increasingly ask: is the claim structurally a product (composition/kit/device), or does it actually recite treatment/diagnostic steps?
In Medilabo, the record shows the applicant specifically complained that the Controller adjudicated the claim based on preamble language and not the claim’s actual structural limitations.
That is exactly the kind of “conclusory” approach courts are pushing back against.
“Allied exclusions”: Section 3(i) logic is spreading to other Section 3 filters
Your question mentions “Section 3(i) and allied exclusions.” The key point is this, once courts demand structured reasoning for Section 3(i), the same discipline inevitably influences other exclusions like, Section 3(k) (computer programs per se/algorithms); Section 3(h) (methods of agriculture/horticulture); Section 3(d) (new forms of known substances without enhanced efficacy)
This doesn’t mean courts dilute exclusions. It means they require the Patent Office to accurately characterize the claimed invention, and apply the exclusion with a clear reasoning path.
(You can see a similar “reasoned, non-mechanical” expectation discussed in wider reporting on Delhi HC scrutiny of Patent Office reasoning in other contexts too, though Section 3(i) judgments are the clearest illustration.)
Practical “IPO-proof” drafting and hearing strategy based on this 2025 pattern
If you’re drafting, replying to FER, or preparing hearing notes for Section 3(i) issues, the 2025 pattern suggests a very practical playbook: a) make characterization unavoidable (claim mapping); provide a claim chart: each claim limitation → where supported in spec → why it is technical/product and not “treatment steps,” if it’s a product claim, say plainly “no method step is claimed; administration is not a claim limitation.”; b) Separate “use” from “claim” acknowledge medical use, but clarify that Section 3(i) excludes processes for treatment, not all inventions in medicine; c) Control preamble risk, if “for treating…” is causing trouble, consider moving medical purpose to description, drafting the claim as a composition defined by structure/ingredients, and or making “for” language explicitly non-limiting (where appropriate). d) In diagnostics: define what your method does not do if you’re in the screening/diagnostic grey zone, explicitly explain whether the method provides a definitive diagnosis or only a risk/screening indicator, whether it requires further confirmatory testing, and what the output is (classification? risk score? detection of a marker?) and how it is used.
The 2025 Section 3(i) batch shows the Court is willing to dive into this distinction so applicants should present it cleanly.
The takeaway in one line
Decisions of 2025 don’t weaken Section 3(i), they strengthen due process and analytical rigor.
 The Patent Office can refuse under subject-matter exclusions, but it must do so through correct claim characterization, and structured, reasoned application of the exclusion especially in borderline cases like diagnostic/screening methods.
Conclusion

Recent patent decisions of the Delhi High Court indicate a significant shift in how Section 3(i) of the Patents Act is being applied. Rather than accepting summary or mechanical refusals by the Patent Office, the Court has stressed the need for detailed and reasoned analysis. It has made it clear that inventions must be correctly characterized based on their claims, not merely on their stated purpose or end use. This approach ensures that genuine technical innovations are not rejected simply because they relate to medical or diagnostic contexts.
By insisting on structured reasoning and careful application of statutory exclusions, the Court has strengthened procedural fairness in patent examination. This evolving judicial stance improves the overall quality and consistency of patent decisions in India. It also provides greater clarity and confidence to innovators and practitioners, encouraging well-reasoned examination practices while maintaining the public interest objectives embedded in Section 3(i).

FAQ's
Q1. What is Section 3(i) of the Indian Patents Act, 1970?
Ans. Section 3(i) excludes any process from patentability for the medicinal, surgical, curative, prophylactic, diagnostic, therapeutic, or treatment of human beings or animals, to ensure that medical treatment remains freely accessible.
Q2. Why is Section 3(i) frequently invoked by the Patent Office?
Ans. The Patent Office often relies on Section 3(i) to reject applications related to medical methods, diagnostics, or treatment processes, sometimes through brief or conclusory reasoning.
Q3. What change is the Delhi High Court bringing through recent patent decisions?
Ans. The Delhi High Court is insisting on a closer judicial review, requiring the Patent Office to provide reasoned, structured, and well-explained findings before rejecting applications under Section 3(i).
Q4. Does the Court allow patents for all medical inventions after these rulings?
Ans. No. The Court has not diluted Section 3(i). It has clarified that exclusions must be applied carefully, based on the true nature of the invention, rather than through broad assumptions.
Q5. What does “closer judicial review” mean in patent appeals?
Ans. It means the Court closely examines whether the Patent Office correctly understood the invention, applied the law properly, and gave adequate reasons for invoking Section 3(i).
Q6. How do these rulings benefit patent applicants?
Ans. Applicants benefit from increased procedural fairness, as summary rejections are more likely to be set aside if they lack detailed reasoning or mischaracterize the invention.
Q7. Are diagnostic or technical devices still patentable despite Section 3(i)?
Ans. Yes, in certain cases. Devices, systems, or technical processes that are not directly treatment methods may still be patentable if properly distinguished and supported in the claims.
Q8. What impact do these decisions have on Patent Office examiners?
Ans. Examiners are now expected to issue well-reasoned orders, clearly explaining how and why an invention falls within Section 3(i), rather than relying on generic objections.
Q9. Will these judgments reduce arbitrary patent refusals?
Ans. Yes. The emphasis on structured reasoning and judicial oversight discourages mechanical or unsupported refusals under Section 3(i).
Q10. What should patent applicants do considering this judicial trend?
Ans. Applicants should draft claims carefully, highlight technical features, distinguish treatment methods from devices or systems, and challenge unjustified Section 3(i) objections through appeals when necessary.

Recent decisions of the Delhi High Court reflect a marked shift toward closer judicial review while interpreting Section 3(i) of the Patents Act, 1970, which excludes methods of treatment, diagnosis, and surgical processes from patentability. Rather than relying on a mechanical application of the statutory bar, the Court has increasingly examined the substance and technical contribution of claimed inventions. This nuanced approach distinguishes between impermissible treatment methods and patent-eligible innovations that demonstrate a tangible technical effect, improved efficacy, or a novel industrial application beyond mere medical procedure. Through these rulings, the Delhi High Court has reinforced a balanced patent jurisprudence one that safeguards public health concerns embedded in Section 3(i) while ensuring that genuine technological advancements are not denied protection merely due to their medical context. This evolving judicial stance signals greater clarity for innovators and practitioners and underscores the Court’s role in aligning patent law with contemporary scientific progress and global best practices.

The shift you’re noticing from “deference” to “discipline”

A visible pattern in 2025 patent appeals (especially before the Delhi High Court’s IPD bench) is that the Court is no longer satisfied with Patent Office refusals that merely quote Section 3(i) and conclude: “therefore non-patentable.” Instead, the Court is increasingly insisting on disciplined, claim-focused reasoning and when the reasoning looks conclusory, it either sets the order aside or remands the matter for fresh consideration with proper analysis.

This is not the Court “lowering” the Section 3(i) bar. Section 3(i) remains a strong exclusion. The change is that the Court is saying, if you want to refuse, you must show your work.

That “show your work” approach appears clearly in the October 9, 2025, batch of decisions interpreting diagnostic-method exclusions under Section 3(i).

Quick refresher: what Section 3(i) excludes (and why it creates disputes)

Section 3(i) excludes from patentability: (i) “any process for the medicinal, surgical, curative, prophylactic, diagnostic, therapeutic or other treatment of human beings,” and (ii) similar treatment of animals to render them free of disease / increase economic value.

On paper, it sounds straightforward, no method-of-treatment patents. In practice, disputes arise because many inventions sit in the grey zone, for example; a composition or kit that is used in treatment (product claims); a diagnostic workflow that uses lab steps and data processing; a “screening” method that might effectively function like “diagnosis”; and inventions where the specification talks about treatment, but the claims are framed as technical steps or products.

So, courts have to repeatedly answer: is the claimed subject matter truly a prohibited “process of treatment/diagnosis,” or is it a patentable technical invention that merely has medical use?

What triggered stricter review in 2025: “conclusory refusals” became a recurring problem

A “conclusory refusal” typically looks like the order describes the invention as treatment/diagnosis (sometimes using the specification’s purpose statements), quotes Section 3(i), and then refuses without mapping each claim element to Section 3(i), explaining how the claim constitutes a “process for treatment/diagnosis,” or addressing the applicant’s amendments/arguments in a structured way.

In other words, the refusal feels like label first, analysis later (or not at all). The Delhi High Court’s 2025 approach pushes back on this and demands, correct characterization of the invention, and a structured chain of reasoning.

You see this strongly in the way the Court frames the issues and then proceeds to analyze Section 3(i) in detail in the 2025 diagnostic-method decisions.

The Court’s method: “characterize first, then apply the exclusion”

A consistent judicial technique in these cases is: Step A: Identify what the claims cover (not merely what the invention is “for”). Courts stress that the scope of the invention must be determined from the claims (read with the specification), not from broad statements like “for treating disease X” or “for diagnosis.”

In the Medilabo v. Controller appeal (C.A.(COMM.IPD-PAT) 16/2024, decided Nov 24, 2025), the dispute itself shows this tension: The applicant argued the claims are composition/kit claims, not treatment methods. The Patent Office position (as recorded) was that the invention is implicitly directed to a dosage regimen/treatment method based on how the specification/examples operate. This is exactly where courts demand careful analysis: Does the claim, as granted/refused, contain treatment steps? Or is it a product claim being refused only because of its eventual medical use?

Step B: Pinpoint the “treatment/diagnostic” element with precision. If the refusal is under Section 3(i), the Controller must identify what part of the claim constitutes a process for treatment/diagnosis, and why that part is not merely an ancillary technical step. In the EMD Millipore matter, the Delhi High Court explicitly frames the interpretive exercise as determining the scope of Section 3(i) for diagnostic methods and whether the subject invention falls within it signaling that Section 3(i) is not applied by label, but by analysis.

Step C: Give a reasoned conclusion (not a summary conclusion)

The Court’s approach effectively imposes a “speaking order” discipline: a] address the applicant’s core arguments, b] deal with amendments, and c] explain why the invention is (or isn’t) excluded.

Diagnostic methods under Section 3(i): why 2025 decisions became a “mini framework”

October 9, 2025, batch (including EMD Millipore and connected prenatal testing appeals such as Sequenom) is important because it treats Section 3(i) diagnostic disputes as a principle-setting question, not just fact disputes.

In Sequenom’s connected appeals, you can see the controversy the Court is dealing with:

Applicant: “This is a screening test, not diagnosis.”

Respondent: relies on statutory definitions under the PCPNDT Act to argue prenatal testing is diagnostic.

The Court heard these in a batch led by EMD Millipore specifically to interpret Section 3(i)’s diagnostic exclusion.

This illustrates the “closer review” pattern, the Court does not accept a simplistic “it’s medical, so excluded.” and it interrogates what counts as “diagnostic” and how “screening vs diagnosis” should be handled in patentability analysis.

This kind of reasoning naturally raises the bar for Patent Office orders: the Controller must show why the claimed method performs diagnosis (or is a diagnostic process), rather than just calling it diagnostic.

“Correct characterization” the heart of the pattern

When courts say “characterization,” they mean: What is the invention, in claim terms?

Not: what the product is intended for, what the specification markets it as, or what the examiner assumes it does.

This matters because: A composition used in treatment is not automatically a “process for treatment.” A kit used for diagnosis is not automatically a “diagnostic process,” and a method that produces a risk score or screening output may or may not be “diagnosis” depending on how the claims are framed and what the output enables.

The Delhi High Court’s insistence on proper characterization is visible in how disputes are presented in cases like Medilabo where the applicant argues the Controller wrongly treated product claims as method claims and also argues that the Controller improperly relied on claim preamble language (purpose statements) rather than limiting steps.

Why courts are sensitive to “preamble” and “end-use” shortcuts

In many pharmaceutical/medical inventions, claims include phrases like: “A composition for treating Alzheimer’s disease”, “A kit for diagnosing condition Y” and A shortcut refusal often happens when: the Controller treats “for treating/for diagnosing” as automatically converting the claim into a Section 3(i) excluded method.

But courts increasingly ask: is the claim structurally a product (composition/kit/device), or does it actually recite treatment/diagnostic steps?

In Medilabo, the record shows the applicant specifically complained that the Controller adjudicated the claim based on preamble language and not the claim’s actual structural limitations.

That is exactly the kind of “conclusory” approach courts are pushing back against.

“Allied exclusions”: Section 3(i) logic is spreading to other Section 3 filters

Your question mentions “Section 3(i) and allied exclusions.” The key point is this, once courts demand structured reasoning for Section 3(i), the same discipline inevitably influences other exclusions like, Section 3(k) (computer programs per se/algorithms); Section 3(h) (methods of agriculture/horticulture); Section 3(d) (new forms of known substances without enhanced efficacy)

This doesn’t mean courts dilute exclusions. It means they require the Patent Office to accurately characterize the claimed invention, and apply the exclusion with a clear reasoning path.

(You can see a similar “reasoned, non-mechanical” expectation discussed in wider reporting on Delhi HC scrutiny of Patent Office reasoning in other contexts too, though Section 3(i) judgments are the clearest illustration.)

Practical “IPO-proof” drafting and hearing strategy based on this 2025 pattern

If you’re drafting, replying to FER, or preparing hearing notes for Section 3(i) issues, the 2025 pattern suggests a very practical playbook: a) make characterization unavoidable (claim mapping); provide a claim chart: each claim limitation → where supported in spec → why it is technical/product and not “treatment steps,” if it’s a product claim, say plainly “no method step is claimed; administration is not a claim limitation.”; b) Separate “use” from “claim” acknowledge medical use, but clarify that Section 3(i) excludes processes for treatment, not all inventions in medicine; c) Control preamble risk, if “for treating…” is causing trouble, consider moving medical purpose to description, drafting the claim as a composition defined by structure/ingredients, and or making “for” language explicitly non-limiting (where appropriate). d) In diagnostics: define what your method does not do if you’re in the screening/diagnostic grey zone, explicitly explain whether the method provides a definitive diagnosis or only a risk/screening indicator, whether it requires further confirmatory testing, and what the output is (classification? risk score? detection of a marker?) and how it is used.

The 2025 Section 3(i) batch shows the Court is willing to dive into this distinction so applicants should present it cleanly.

The takeaway in one line

Decisions of 2025 don’t weaken Section 3(i), they strengthen due process and analytical rigor.

The Patent Office can refuse under subject-matter exclusions, but it must do so through correct claim characterization, and structured, reasoned application of the exclusion especially in borderline cases like diagnostic/screening methods.

Conclusion

By insisting on structured reasoning and careful application of statutory exclusions, the Court has strengthened procedural fairness in patent examination. This evolving judicial stance improves the overall quality and consistency of patent decisions in India. It also provides greater clarity and confidence to innovators and practitioners, encouraging well-reasoned examination practices while maintaining the public interest objectives embedded in Section 3(i).

FAQ's

Q1. What is Section 3(i) of the Indian Patents Act, 1970?

Ans. Section 3(i) excludes any process from patentability for the medicinal, surgical, curative, prophylactic, diagnostic, therapeutic, or treatment of human beings or animals, to ensure that medical treatment remains freely accessible.

Q2. Why is Section 3(i) frequently invoked by the Patent Office?

Ans. The Patent Office often relies on Section 3(i) to reject applications related to medical methods, diagnostics, or treatment processes, sometimes through brief or conclusory reasoning.

Q3. What change is the Delhi High Court bringing through recent patent decisions?

Ans. The Delhi High Court is insisting on a closer judicial review, requiring the Patent Office to provide reasoned, structured, and well-explained findings before rejecting applications under Section 3(i).

Q4. Does the Court allow patents for all medical inventions after these rulings?

Ans. No. The Court has not diluted Section 3(i). It has clarified that exclusions must be applied carefully, based on the true nature of the invention, rather than through broad assumptions.

Q5. What does “closer judicial review” mean in patent appeals?

Ans. It means the Court closely examines whether the Patent Office correctly understood the invention, applied the law properly, and gave adequate reasons for invoking Section 3(i).

Q6. How do these rulings benefit patent applicants?

Ans. Applicants benefit from increased procedural fairness, as summary rejections are more likely to be set aside if they lack detailed reasoning or mischaracterize the invention.

Q7. Are diagnostic or technical devices still patentable despite Section 3(i)?

Ans. Yes, in certain cases. Devices, systems, or technical processes that are not directly treatment methods may still be patentable if properly distinguished and supported in the claims.

Q8. What impact do these decisions have on Patent Office examiners?

Ans. Examiners are now expected to issue well-reasoned orders, clearly explaining how and why an invention falls within Section 3(i), rather than relying on generic objections.

Q9. Will these judgments reduce arbitrary patent refusals?

Ans. Yes. The emphasis on structured reasoning and judicial oversight discourages mechanical or unsupported refusals under Section 3(i).

Q10. What should patent applicants do considering this judicial trend?

Ans. Applicants should draft claims carefully, highlight technical features, distinguish treatment methods from devices or systems, and challenge unjustified Section 3(i) objections through appeals when necessary.