Part II – The Legal Battle Lines: Trademark Infringement, Reputation and the Limits of Brand Exclusivity
Missed Part I? Catch up on how the “6E” dispute began before diving into the legal battle.
Section IV — Procedural History
The litigation between InterGlobe Aviation and Mahindra Electric has moved through the Delhi High Court in four distinct phases: filing, interim resolution, mediation, and the present pre-trial stage. Each phase has something to tell us, not just about this dispute, but about how India’s commercial courts manage high-profile brand conflicts.
Filing and the First Hearing. IndiGo filed its trademark infringement suit before the Delhi High Court in December 2024. The matter was initially placed before Justice Amit Bansal, who recused himself without stating reasons, a routine judicial event, but one that added several weeks to the timeline before relisting. Justice Mini Pushkarna took up the case. Rather than immediately pressing for an interim injunction, IndiGo took a tactically considered position: it waived the application for interim relief once Mahindra gave its undertaking in court (recorded by Justice Pushkarna on December 9, 2024) not to use “BE 6e” for the duration of proceedings and to market the vehicle as “BE 6.” The court disposed of the interim application and scheduled the matter for pleadings in April 2025. IndiGo had secured the commercial outcome it needed immediately: the disputed mark was off the market without the risk of an adverse interim order finding that no prima facie case existed.
Mediation and Its Failure. With pleadings complete, the matter was referred to mediation; both because the Delhi High Court’s practice in commercial disputes leans toward structured settlement attempts, and because Section 12A of the Commercial Courts Act, 2015 reflects a legislative preference for pre-trial resolution. It mandates that a plaintiff must exhaust pre-institution mediation before filing a commercial suit, unless the suit requires urgent interim relief. Introduced via a 2018 amendment, the provision aims to reduce court congestion and promote amicable settlements in the “ease of doing business. In practice, that preference has proven difficult to translate into outcomes. A 2023 EAC-PM Working Paper found that between 2020 and 2023, nearly 98 per cent of pre-institution mediation applications in Mumbai district courts were non-starters, with only 1 per cent resulting in successful settlements. A figure that reflects the structural reality that parties with genuine disputes about principle, rather than quantum, rarely settle in mediation. The IndiGo-Mahindra dispute is precisely that kind of case: the commercial exposure is limited (Mahindra had already renamed the vehicle), but the legal question, whether a well-known alphanumeric mark can attract cross-sector protection, is one that neither party can concede without consequences for its broader brand strategy. Mediation was formally confirmed as having failed on October 31, 2025, when Joint Registrar (Judicial) Sudhir Kumar Sirohi noted that the issue could not be settled through mediation and directed both parties to file photocopies of relevant documents and prepare a joint schedule of documents
Section V — Why This Case Matters: The Questions That Keep IP Lawyers Awake
Let us set aside, for a moment, the specific facts: the airline, the SUV, the compromise of “BE 6.” Let us set aside even the outcome, which remains, as of mid-2026, undecided. What makes InterGlobe Aviation v. Mahindra Electric genuinely important is not what the court will decide about these two parties. It is what the court’s reasoning will reveal about the rules that govern every brand owner, every product team, and every trademark counsel in India operating in the same constrained commercial landscape. The case is a pressure test for four propositions that Indian trademark law has never cleanly resolved. Each one deserves to be examined on its own terms, because each one has consequences that reach far beyond aviation and automobiles.
Can Two Characters Be Owned?
Start with the most discomforting question: can a single number and a single letter, combined, constitute a valid trademark that one party can assert against the world?
The instinctive answer, at least outside a lawyer’s office, is no. Numbers and letters are the shared raw material of commerce. They are the building blocks from which every product name, SKU code, model designation, and identifier in every industry is assembled. Allowing one company to monopolise a two-character combination feels like allowing someone to own a syllable.
But trademark law does not work from instinct, and the instinct here is wrong — or at least, incomplete. A mark does not acquire protection because of what it looks like in isolation. It acquires protection because of what it means to the relevant public after years of continuous and distinctive use. “3M” is three characters. “BMW” is three letters that mean nothing in English. “DHL” tells you nothing about what it ships or where. These marks are protected not despite their brevity but because of it, because brevity, combined with relentless consistent use, produces the kind of concentrated recognition that trademark law exists to protect.
The real question, then, is not whether two characters can be owned. They can, and frequently are. The real question is a more precise one: when does a two-character mark become famous enough that the law will protect it against uses in industries entirely different from the one in which it was built? That is IndiGo’s actual claim, and it is a claim that Indian law has answered inconsistently, case by case, without clear doctrinal architecture.
In early 2026, the Delhi High Court refused to grant interim protection to Alkem Laboratories over its “A to Z” marks in a dispute against Prevego Healthcare, holding that English alphabets and commonly used expressions cannot be monopolised under trademark law1. That ruling, delivered in the same court now considering the IndiGo claim, reflects an important counter-principle: distinctiveness is not assumed from brevity. It must be demonstrated from use. IndiGo can demonstrate that use. The question is whether the use is distinctive enough and specific enough to reach across industry lines. The Alkem ruling tells us that the burden of proof is real and that the presumption runs against the claimant of a short mark. IndiGo must earn its protection on evidence, not on the intrinsic character of the identifier.
Does a Famous Mark Follow Its Owner Everywhere?
The second question is the doctrinal heart of the case, and it is one that Indian trademark law has approached with notable ambivalence.
Section 29(4) of the Trade Marks Act, 1999 provides that a registered mark with a reputation in India is infringed by use of an identical or similar mark in relation to dissimilar goods or services, if that use takes unfair advantage of or is detrimental to the distinctive character or repute of the registered mark. This is India’s partial codification of the dilution doctrine; and the word “partial” carries significant weight. Unlike the United States, India lacks any standalone dilution doctrine. Section 29(4) partially fulfils this void by protecting well-known trademarks against use on dissimilar goods that tarnishes their reputation and goodwill, but the trademark dilution doctrine remains underdeveloped, nascent, and subsumed within the concept of well-known trademarks.
This gap has structural consequences for cases exactly like IndiGo’s. To invoke Section 29(4), IndiGo must first establish that “6E”, or more precisely, “6E Link” as a registered mark, has a reputation in India sufficient to attract cross-sector protection. That standard is higher than mere recognition. It demands that a substantial segment of the Indian public knows the mark, and that they know it with sufficient depth of association that a court can find the Mahindra use either takes unfair advantage of that association or is detrimental to it.
The Delhi High Court’s 2026 ruling in Columbia Pictures v. Registrar of Trade Marks clarified that Section 11(2) protects well-known trademarks even against registration for dissimilar goods, and that a prior formal declaration of well-known status under Rule 124 is not essential to claim that protection; evidence of reputation can be evaluated during opposition proceedings. That ruling marginally assists IndiGo: it means the airline does not need to have formally secured well-known mark status before the Registry in order to assert the claim before the court. But it does not resolve the deeper question: whether the reputation IndiGo has built in the aviation sector, for a mark registered only in Classes 9, 16, 35, and 39, is sufficient to prevent a completely separate commercial actor in the automotive sector from using the same characters in a composite designation.
There is also a troubling structural question that the court will have to address, whether it wants to or not: IndiGo’s registered mark is “6E Link,” not the bare “6E.” Cross-sector protection under Section 29(4) flows from a registered mark with reputation. If the registered mark is a composite, “6E Link” does the cross-sector protection extend to every use of the element “6E” alone, or only to uses sufficiently similar to the composite? The court’s answer will have consequences for every brand owner who has registered a composite mark and now wishes to use that registration to protect an element of it
| Point to be noted When IndiGo filed for “6E Link” in 2015, they deliberately secured it across four distinct trademark classes • Class 9: For illuminated signage and digital media. • Class 16: For printed advertising materials and boards. • Class 35: For advertising, business management, and promotional services. • Class 39: For transport, travel arrangements, and aviation-related services |
Is There a Public Right to Use Common Alphanumeric Expressions?
The third question is the one Mahindra pressed publicly, but which deserves a more rigorous framing than it typically receives: is there a public interest in keeping short alphanumeric combinations available for use, and if so, what is its source and its limit?
Mahindra’s stated concern about monopolisation of short alphanumeric marks is not merely a litigation tactic. It reflects a genuine structural tension in trademark law between incentivising brand investment and preserving the common commercial language that all businesses need. The alphabet has twenty-six letters. The digits run from zero to nine. Two-character alphanumeric combinations from this set produce, at most, a few hundred permutations. If each industry’s dominant brand can lock up one or more of these combinations against all other industries, the available naming space for new market entrants narrows in ways that competition policy should care about.
The US doctrine of “aesthetic functionality” and the EU concept of “public interest in keeping certain signs available” both gesture at this concern, without fully resolving it. Indian trademark law has no direct equivalent, but the courts have occasionally signalled awareness of the problem. The Alkem ruling, declining to protect “A to Z” on the grounds that alphabetical expressions cannot be monopolised, reflects precisely this concern applied to alphabetical marks. The IndiGo case will test whether that instinct extends to alphanumeric combinations when the claimed mark has been used consistently and with significant commercial investment.
How Much Exclusivity Is Too Much? The Question the Judgment Cannot Avoid
The fourth question is, in some ways, the most philosophically interesting, and the least tractable.
Trademark law has always lived with an internal tension. Its premise is that distinctive marks deserve exclusive protection, because that exclusivity incentivises the brand investment that benefits consumers through quality signalling. But exclusivity, extended too far, becomes a tax on commerce; a toll that competitors must pay to enter naming space that has been, in effect, privatised. Every extension of cross-sector protection narrows the field for the next entrant. Every well-known mark declaration creates a penumbra of restriction that reaches beyond the sector of registration. At some point, the incentive to invest in brand distinctiveness flips into the disincentive to compete at all.
India’s trademark jurisprudence has not yet produced a clear articulation of where that line falls for marks that are short, alphanumeric, and famous in one sector but claimed against another. The closest the courts have come is in the well-known mark cases (Whirlpool, Daimler Benz, Toyota) where protection was extended to marks with genuinely vast public recognition. But those cases involved word marks with globally iconic associations, not two-character identifiers built in a single domestic sector.
The IndiGo-Mahindra case is different in kind. “6E” is not globally famous. It is not a household name across India in the way that “Whirlpool” or “Toyota” is. It is famous within a specific consumer context (air travel) to a specific consumer population; the estimated 10 to 12 crore passengers IndiGo carries annually. That is a large number in absolute terms. Whether it constitutes the kind of public-segment saturation that justifies extending protection into an entirely unrelated consumer market, the market for electric SUVs, is a question of degree that the court must answer with reference to evidence, not intuition.
What makes the answer consequential, and what makes practitioners across India watch this case with unusual attention, is that the Delhi High Court’s reasoning, whatever its conclusion, will become the standard by which every future cross-sector mark claim in India is assessed. A ruling that IndiGo’s “6E” is famous enough will be cited by every brand owner in every sector seeking to extend a short mark’s reach. A ruling that it is not that two-character identifiers, however extensively used, cannot travel across sectoral lines without more will recalibrate IP filing and enforcement strategy across the country.
D&D Commentary: What This Case Will Decide and Why It Matters to Your Brand
It’s time to look at both sides of the coin.
IndiGo’s Case in Summary
IndiGo’s argument rests on four pillars, each reinforcing the next.
The first is reputation. Nineteen years of continuous use of “6E” across every consumer touchpoint, such as boarding passes, livery, digital platforms, advertising, have created public recognition that no brand survey is needed to establish. An estimated 10 to 12 crore passengers annually have encountered “6E” as the identifying mark of IndiGo’s operations. That volume of exposure, sustained over nearly two decades, is the factual foundation for everything that follows.
The second is goodwill. Reputation is recognition. Goodwill is what that recognition is worth. IndiGo’s submission is that “6E” carries not just awareness but a specific commercial association, with reliability, with price-consciousness, with a particular standard of domestic air travel. It has been built through sustained investment and that constitutes a property right the law must protect. Goodwill, once established, belongs to its owner. Conduct that threatens to dilute or appropriate it causes harm that equity has always recognised.
The third is dilution. This is where IndiGo’s case moves from the familiar to the legally contested. The dilution argument under Section 29(4) of the Trade Marks Act, 1999 does not require proof of consumer confusion. It requires proof that the defendant’s use, identical or similar to a mark with reputation, either takes unfair advantage of the mark’s distinctiveness or is detrimental to it. IndiGo’s position is that “BE 6e,” even in the automotive sector, draws on the mental association consumers have already formed between “6E” and IndiGo, and that permitting such use weakens the mark’s capacity to function as an exclusive identifier. A two-character mark is only as strong as its exclusivity. Each new association erodes that strength, whether or not any consumer is actively deceived.
The fourth is exclusivity as a principle: the argument that a well-known mark, once earned, must be capable of protection across the commercial landscape without the owner being required to register preemptively in every class in which infringement might theoretically arise. If cross-sector protection is unavailable to a mark with IndiGo’s depth of recognition, the well-known mark provisions of the Act are materially weaker than their drafting suggests.
Mahindra’s Case in Summary
Mahindra’s response is equally structured, and its logic is not without force.
The first argument is unrelated industries. The core of Mahindra’s submission is that “BE 6e” was adopted for motor vehicles in Class 12, a class in which IndiGo has no registration and has never operated. The Trademark Registry accepted Mahindra’s application without finding a prima facie conflict. The sectors are distinct, the consumers are distinct, the channels of purchase and use are distinct. No reasonable consumer browsing an electric SUV is forming a view about airline services. The possibility of confusion, the traditional test for infringement, is, on Mahindra’s case, negligible to non-existent.
The second argument is the composite mark. Mahindra did not adopt “6E” alone. It adopted “BE 6e” as a composite designator within a structured product architecture: “BE” for Born Electric, the numeric model indicator, and “e” as an electrification suffix. Each element is defined. None was chosen to invoke IndiGo. The composite mark, taken as a whole, does not resemble “6E” or “6E Link” in visual impression, conceptual meaning, or commercial context. Mahindra’s further submission that “e” as an electrification suffix is used across the automotive industry by BMW (iX, i4), Mercedes (EQE, EQS), Volkswagen (ID.4, ID.5), and others is not merely comparative. It is an argument that if “e” in the automotive context is generic, no airline’s mark in an entirely different class can appropriate it.
The third is legitimate adoption. Mahindra’s position is that its naming architecture was constructed independently, purposefully, and with a creative internal logic. The “BE Sexy” phonetic resonance that the launch narrative made public, the Born Electric platform identity, and the numeric model hierarchy. A company that builds a coherent naming system from defined internal elements, and can demonstrate that construction process, has a legitimate adoption defence. Appropriation of goodwill requires showing that the defendant chose its mark to benefit from the plaintiff’s reputation. Mahindra’s case is that its creative and commercial logic pointed to “6e” from the inside, not toward “6E” from the outside.
What the Court Must Decide
The parties’ positions identify three questions for which Indian trademark law currently has no clean answer, and on which the Delhi High Court’s reasoning, whatever its outcome, will constitute a binding contribution to doctrine.
First: Does the bare mark “6E,” used as an identifier since 2006, attract the cross-sector protection that the registered composite mark “6E Link” would confer only if established as a well-known mark? The court must address IndiGo’s unregistered rights in “6E” and determine whether the considerable evidence of use translates into legal protection of sufficient breadth.
Second: Does India’s Section 29(4) dilution provision require proof of actual consumer confusion, or is proof of mental association, that consumers link “6e” to IndiGo even without being deceived, sufficient? This is the doctrinal gap that the case will either close or expose. India lacks a standalone dilution statute. Whether Section 29(4) can do the work that IndiGo needs it to do is a live statutory question.
Third: Where does the public interest in keeping alphanumeric combinations available for legitimate commercial use set a limit on brand exclusivity? The court cannot ignore Mahindra’s structural argument that allowing one company to control a two-character identifier across all industries has consequences for the naming landscape that reach beyond the parties before it.
IndiGo’s claim, if accepted, will establish that consistent, long-term, high-volume use of an alphanumeric identifier in one industry can generate cross-sector trademark protection even where the registered mark is a composite. It will encourage brand owners across India to invest in building mark distinctiveness in the confidence that such investment earns durable, broad rights. It will also make the naming landscape for every new market entrant marginally more constrained.
Mahindra’s defence, if accepted, will establish that cross-sector protection for short marks requires a clearer and more demanding showing of reputation and harm than IndiGo’s evidence supports, and that composite marks used in distinct industries do not infringe the root elements of other parties’ marks merely by phonetic or visual resemblance. It will preserve more of the alphanumeric naming space for legitimate commercial use, at the cost of narrowing the protection available to marks that have been built with genuine investment.
Neither outcome is wrong. Both are defensible from within Indian trademark law as it currently stands. What is needed, and what this case will provide, one way or another is a clear and reasoned statement of the principle that chooses between them. That statement, when it comes, will be the case’s true legacy: not a ruling about an airline and a car company, but a ruling about what it means, in twenty-first-century India, to own a mark.
The dispute between IndiGo and Mahindra is unlikely to be remembered merely because it concerns two characters: “6E”. Rather, it may become a defining precedent in determining how Indian trademark law balances proprietary rights against competitive freedom in an economy where brands increasingly transcend products, industries, and traditional commercial boundaries. As businesses continue to adopt minimalist and globally recognisable identifiers, the legal principles emerging from this litigation are likely to influence trademark strategy, enforcement, and brand management for years to come.
Regardless of the eventual outcome, the dispute reinforces an enduring principle of trademark law: the true strength of a trademark lies not merely in registration, but in the reputation it earns, the goodwill it embodies, and the consumer trust it commands. For brand owners navigating increasingly crowded and interconnected markets, protecting these intangible assets requires not only legal registration but also strategic foresight, consistent brand stewardship, and proactive intellectual property management.
| Status as at July 2026: The matter is listed before the Delhi High Court and is at the stage of admission, denial, and marking of exhibits. Parallel opposition proceedings before the Trade Marks Registry remain pending. This article will be updated when a judgment or significant order is pronounced. For the latest status, see the D&D IP Repository. |
