On March 12, 2026, a bench of the Supreme Court of India comprising Chief Justice Surya Kant, Justice Joymalya Bagchi and Justice Vipul Pancholi formally disposed of Writ Petition (Civil) No. 13029 of 1985 – M.C. Mehta v Union of India. The bench simultaneously directed the Registry to register a fresh suo motu proceeding titled In Re: Issues of Air Pollution in the National Capital Region. On the face of it, it is a renumbering exercise to correct a statistical anomaly in the court’s pendency data. However, it marks the end of a 40-year constitutional experiment in judicial environmental governance.Origins: The 1985 petition and the doctrine it generatedMahesh Chander Mehta was an environmental lawyer who, in 1985, filed a public interest litigation under Article 32 of the Constitution arguing that vehicular and industrial pollution in Delhi had reached levels incompatible with the right to life guaranteed by Article 21. The case number was WP(C) 13029/1985. This specific petition was the Delhi air pollution and vehicular emissions case. Mehta filed several distinct PIL petitions in this period – on Ganga pollution, on the Taj Mahal and the Taj Trapezium Zone, and others – all of which carry his name but bear different writ petition numbers. Thursday’s disposal order was confined to WP(C) 13029/1985. The Ganga and Taj matters were not closed.What distinguished the 1985 petition was not merely its subject matter but the procedural innovation it licensed. The Supreme Court found that the conventional writ of mandamus – a one-time command to a public authority to perform a duty – was structurally inadequate to address a problem as complex and continuous as urban air pollution. The executive had not just failed to act once; it had consistently failed to implement environmental law across administrations, and that failure was structural and ongoing. The court’s response was to evolve what scholars and the court itself now call the ‘continuing mandamus’: a writ remedy under which the bench issues directions periodically, retains jurisdiction indefinitely, and monitors implementation over years and decades.It is important to note that the term ‘continuing mandamus’ was formally coined by the Supreme Court not in an environmental case but in Vineet Narain v. Union of India (1998), the Jain Hawala case, where the court used it to monitor a stalled CBI investigation against high-profile individuals. The court described it as a new tool forged because of peculiar circumstances. The practice, however – keeping a case alive and issuing successive supervisory directions – had been operational in the M.C. Mehta matters and in the parallel T.N. Godavarman Thirumulpad forestry case since the early 1990s. The legal architecture of continuing mandamus was, in effect, pioneered in environmental PIL before it acquired a formal name.The constitutional grounding for this expansion ran through Article 21, read alongside the Directive Principle in Article 48A – which directs the state to protect and improve the environment – and the fundamental duty in Article 51A(g), which enjoins citizens to do the same. These latter provisions are not themselves enforceable fundamental rights, but the court used them to give content to the right to life. In Virender Gaur v. State of Haryana (1995) and Vellore Citizens Welfare Forum v. Union of India (1996), the court held explicitly that the right to a healthy and pollution-free environment was an integral element of Article 21. The M.C. Mehta litigation was one of the principal arenas in which this jurisprudence was developed.What the case producedOn emissions, the trajectory ran from the court’s 1990 acknowledgement that heavy vehicles were the primary drivers of Delhi’s pollution, through a series of escalating directions, to its constitution of the Environment Pollution (Prevention and Control) Authority – the EPCA – under the Environment (Protection) Act, 1986. The EPCA functioned as the court’s expert technical adviser, recommending policy measures which the bench would then convert into judicially binding orders. It was substantially on the basis of EPCA recommendations that the court, around 1998, directed that Delhi’s entire bus fleet – public and private – be converted from diesel to compressed natural gas (CNG), with a deadline of March 31, 2001.The government repeatedly sought extensions, citing a shortage of CNG filling stations, logistical delays, and the supply-demand circular problem between bus manufacturers and infrastructure providers. The court held firm. The deadline was missed; in 2002, the court fined the Delhi government Rs 1,000 per diesel bus per day still operating on its roads. The last diesel bus was removed from Delhi’s streets in December 2002 – roughly 18 months past the original deadline. A study by Narain and Bell (Resources for the Future), tracking Delhi’s air quality from 1990 to 2005, found that the conversion of public transport to CNG had the most significant measurable impact on reducing particulate pollution. A 2004 World Bank assessment estimated that the conversion helped prevent over 3,600 premature deaths annually in Delhi alone.The second cluster concerns industrial relocation. From 1995, the court issued a series of orders directing the closure or relocation of industrial units operating in residential and non-conforming areas in violation of Delhi’s Master Plan. A 1995-96 survey by the Delhi Pollution Control Committee found approximately 1,01,000 industrial units in non-conforming areas, employing an estimated seven lakh workers. The court began with the 168 most heavily polluting units in 1996 and expanded the scope progressively; by 2000, it was directing the relocation of all non-conforming industrial units in the city.The costs that were not countedThe industrial relocation orders are where the continuing mandamus model most visibly strained against its constitutional limits. Closing and relocating tens of thousands of units was a major policy intervention with enormous socio-economic consequences – precisely the kind of intervention that, in a functioning legislature, would have been preceded by parliamentary debate, statutory design, and compensatory mechanisms for displaced workers. Because the intervention arrived through judicial orders under a PIL, none of those procedures applied. Workers displaced from the 1,01,000 non-conforming units had no electoral recourse against the decision-makers. The burden fell hardest on those least able to absorb it: small operators and daily-wage workers at the bottom of Delhi’s manufacturing economy.On vehicular pollution, a parallel irony applies. The gains from the CNG conversion were real but were substantially eroded by the growth in private diesel and petrol vehicles, over which the court had no comparable leverage. Delhi’s registered vehicle count has grown from under four million in the early 2000s to over twelve million by the mid-2010s. The continuing mandamus addressed one segment of the transport problem with extraordinary judicial energy; the larger structural failure of urban planning and public transport investment remained, and remains, essentially beyond judicial reach.There is also a separation-of-powers objection that deserves honest engagement. Former Chief Justice A.S. Anand observed that a court using continuing mandamus must be careful not to treat a matter as an ongoing process for an indefinite period – that the court’s role is to set the process of implementation in motion, not to become a permanent super-administrator. The M.C. Mehta docket came close to defying that caution. The court was, at various points, directing the location of filling stations, setting deadlines for bus manufacturers, monitoring industrial estate allotments, and overseeing the implementation of Delhi’s Master Plan. Whether this constitutes the court stepping into the executive’s shoes – or filling a void left by an absent executive – is a question that does not admit of a clean answer.The statistical problem and the procedural solutionChief Justice Surya Kant first raised the disposal question at a hearing on February 23, 2026, noting that a 1985 petition appearing as ‘pending’ was an embarrassment when Parliament inquired about the court’s docket. The bench identified the mechanism precisely: fresh grievances that should have been filed as independent writ petitions were instead routed as interlocutory applications into the 1985 file. By the time of Thursday’s order, M.C. Mehta alone carried 85 pending interlocutory applications. The bench noted that none of the issues that still survive originated in 1985 or soon thereafter.The solution is procedurally clean. All 85 pending interlocutory applications are directed to be re-registered as independent writ petitions with their own case numbers. Advocates on Record have two weeks to inform the Registry whether their applications remain live; those that cannot demonstrate continuing relevance will be treated as infructuous and dismissed. The fresh suo motu proceeding absorbs the substantive monitoring work going forward. Senior Advocate Aparajita Singh, serving as amicus, and Additional Solicitor General Aishwarya Bhati, for the Union, both endorsed the proposal. All parties were, as the bench put it, ad idem.What the new proceeding changes – and what it does notThe optimistic reading of Thursday’s order is that it signals a genuine institutional shift: from the omnibus, ever-expanding model of WP(C) 13029/1985 to a more disciplined, issue-specific framework in which each grievance must stand on its own constitutional footing. The indefinite accretion that characterised the original case – where a petition about Delhi’s buses came to encompass commercial sealing, and the regulation of industrial estates across the NCR – will be harder to replicate within a proceeding that consciously limits itself to air quality.The more sceptical reading is that the court has solved only the statistical embarrassment, not the structural question. The new suo motu proceeding is still a proceeding before the Supreme Court. The CAQM is still the regulatory body in the field. Amicus counsel will still assist the bench. Continuing mandamus by a fresh case number is still continuing mandamus. If the concern is that four decades of intensive judicial supervision have served partly as a substitute for, rather than a driver of, sustained legislative and executive action on air quality, the answer cannot be found in a renumbering exercise.A final reckoningThe M.C. Mehta litigation of 1985 arose in a specific institutional moment: a constitutional court expanding its jurisdiction in response to near-total executive failure, using procedural innovation in the absence of specialist environmental courts or robust statutory enforcement machinery. That moment has changed. The National Green Tribunal has existed since 2010. The CAQM now has a statutory basis. The doctrines pioneered in this litigation – the right to a healthy environment under Article 21, the polluter pays principle, the precautionary principle – are embedded in the legal fabric.What has not changed is Delhi’s air. The AQI regularly breaches hazardous thresholds every winter. The structural drivers – thermal power generation, agricultural stubble burning in Punjab and Haryana, the growth in private vehicle ownership – persist. In that sense, the closure of WP(C) 13029/1985 closes a chapter without ending the story.The question for the new suo motu proceeding is whether the next phase of Delhi’s environmental governance will continue to be driven from the docket of one court, or will finally find its home in the statutory frameworks, budgetary commitments, and political accountability that durable environmental protection actually requires. A new case number alone cannot answer that.