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Introduction:-
The Supreme Court's November 2025 ruling on the Aravalli range has started widespread debate, with critics arguing that it weakens environmental safeguards by permitting certain mining activities to continue. The Court, however, has presented the decision as a corrective measure aimed at addressing legal gaps, curbing illegal mining, and establishing a uniform and enforceable framework for protecting this ecologically fragile hill system. In this article, we will examine the significance of two foundational environmental doctrines the Precautionary Principle and the Polluter Pays Principle and explore how they guide judicial intervention and governance in cases like the Aravallis.
What is a precautionary principal?
The precautionary principle originated in German environmental law in the 1970s, known as the Vorsorgeprinzip (literally, the "foresight" or "prevention" principle).1 It was developed as a policy approach that required the State to anticipate and prevent environmental harm before it occurs, rather than reacting after damage has been caused. From Germany, the principle gradually entered European environmental policy and later international environmental law, especially during the 1980s and 1990s, as environmental risks became more complex, uncertain, and potentially irreversible. Its global recognition was firmly established at the 1992 Rio Earth Summit, where it was formally articulated in the Rio Declaration on Environment and Development.
I Definition of the Precautionary Principle
The precautionary principle holds that where there are threats of serious or irreversible environmental damage, the lack of full scientific certainty should not be used as a reason for postponing cost-effective measures to prevent environmental degradation. In essence, it shifts the focus from reacting to environmental harm to preventing harm in advance and often places the burden of proof on the actor proposing potentially harmful activity.2
The Rio Declaration on Environment and Development 1992, adopted at the United Nations Earth Summit in Rio de Janeiro, is a non-binding international instrument comprising 27 guiding principles designed to harmonise environmental protection with economic development through the framework of sustainable development. It articulates foundational norms such as the precautionary principle, polluter pays principle, intergenerational equity, and public participation, while recognising the responsibility of States to prevent environmental harm within and beyond their territorial limits.
II Principle 15 of the Rio Declaration (1992) states:
"In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation."3
This article situates the ongoing controversy over the Supreme Court's 2025 redefining of "Aravalli Hills" within this jurisprudence. It contrasts the Court's earlier precautionary, ecosystem-centric interventions in M.C. Mehta and Godavarman with the more recent elevation-based definition and examines whether the latter is consistent with the Precautionary Principle as constitutionally understood.
A. Significance of Aravalli Hills as an Ecological System.
The Aravalli Hills are among the oldest geological formations in India, stretching discontinuously from Delhi through Haryana and Rajasthan into Gujarat. They perform multiple, interlinked ecological functions:
- Desertification barrier: The range acts as a "green wall" limiting the eastward expansion of the Thar Desert. Its degradation risks the collapse of this barrier, allowing dust storms and arid conditions to advance into Delhi NCR and fertile parts of Haryana and Rajasthan.4
- Groundwater recharge: The hills and their pediments (slopes) function as critical groundwater recharge zones. Mining and construction disrupt natural fractures and percolation pathways, contributing to the emergence of "dark zones" where groundwater tables have dropped by hundreds of feet.
- Green lungs & carbon sink: The Aravalli's vegetation acts as a regional carbon sink and filters particulate pollution (PM2.5, PM10) affecting Delhi–NCR. Loss of this cover exacerbates already severe air quality problems.5
- Wildlife corridor: The range provides corridor connectivity for leopards, hyenas and other fauna between protected areas such as Sariska and Ranthambhore. Fragmentation by highways and real estate development severs these corridors and intensifies human–wildlife conflict.6
These characteristics have been repeatedly recognised, implicitly and explicitly, in the Court's Aravalli jurisprudence, particularly in the mining bans in Haryana and the insistence on sustainable development in M.C. Mehta v. Union of India (2004, 2009). 7
B. The Pre-existing Protection Regime
Prior to the 2025 definitional controversy, the Aravalli regime comprised an interlocking framework of central notifications and state-level measures:
- Environment (Protection) Act notification (1992): Notification S.O. 319(E) under Section 3(2)(v) of the Environment (Protection) Act, 1986 prohibited new mining operations (including renewals) and specified that any such activities in notified Aravalli areas required prior central permission, with a mandatory environmental impact statement and management plan
- Land & forest classification: The 1992 notification identified Aravalli areas through forest classifications and revenue categories such as Gair Mumkin Pahar, with state-specific mechanisms including Section 4 orders under the Punjab Land Preservation Act in Haryana and forest notifications over the Delhi Ridge under the Indian Forest Act.
- Supreme Court oversight: For over four decades, the Supreme Court in MC Mehta and Godavarman proceedings supervised restrictions on tree felling and mining in forest and Aravalli areas, using monitoring committees and expert reports. Together, these measures formed a fragmented but effective protective framework for the Aravallis.
This framework, although complex and fragmented between central and state instruments, provided a broadly coherent protective canopy over the Aravalli landscape.
III. Evolution of the Precautionary Principle in Indian Environmental Jurisprudence
The Precautionary Principle entered Indian environmental law through judicial interpretation rather than legislation. In Vellore Citizens' Welfare Forum v. Union of India (1996)8, concerning pollution of the Palar River by tanneries, the Supreme Court held that economic benefits cannot justify environmental degradation and declared the Precautionary Principle and Polluter Pays Principle to be part of Indian law under Article 21. Justice Kuldip Singh articulated three elements of precaution:
- authorities must anticipate and prevent environmental harm,
- lack of scientific certainty cannot justify inaction,
- the burden of proving environmental safety lies on the developer.
This doctrinal foundation was subsequently applied and expanded in later cases.
M.C. Mehta, Kamal Nath, Nayudu and Godavarman
The Court moved from recognising the Precautionary Principle to applying it in concrete cases. In M.C. Mehta matters relating to Badkhal and Surajkund lakes, construction was restricted on the ground that ecology and public health take precedence over revenue and employment. In M.C. Mehta v. Kamal Nath (1997)9, involving diversion of the Beas river for a private resort, the Court reaffirmed that precaution and polluter pays are essential components of sustainable development and part of Indian law. In A.P. Pollution Control Board v. M.V. Nayudu, the Court expressly endorsed Rio Principle 15, and in T.N. Godavarman (2022), it reaffirmed that precaution is constitutionally required, holding that even a justified environmental risk or doubt must be resolved in favour of environmental protection.
IV. Aravalli Mining Cases: Precaution in Practice
The Aravalli mining litigation demonstrates the operationalisation of the Precautionary Principle. In M.C. Mehta v. Union of India (2004), the Court examined reports of the Central Empowered Committee documenting unregulated mining in the Aravallis of Faridabad and Gurgaon, including mining without environmental clearance, groundwater depletion, ecological damage and safety violations. The Court invoked Articles 21, 47, 48A and 51A(g), relied on Rio Principle 15, and warned that if strict conditions failed, a complete mining ban might be necessary, stressing that the Aravalli range must be protected at any cost.
Suspension of Mining in 2009
In M.C. Mehta (2009), the Supreme Court found continued noncompliance with mining and environmental laws and reiterated that environment and ecology are national assets governed by intergenerational equity. Distinguishing between balancing and banning under sustainable development, the Court suspended mining over approximately 448 square kilometres of the Aravalli hills in Haryana until a scientifically verified reclamation and restoration plan was implemented. This decision exemplifies the application of precaution where uncertain but potentially irreversible ecological harm justified halting economic activity.
Godavarman Line: Minimal Disturbance and Expert Oversight
In the Godavarman series, including the 200910 decision concerning iron ore mining, the Court consistently emphasised minimal disturbance to ecologically sensitive and forested areas. It directed expert led rehabilitation, scientific assessment of slope stability, and supervised mine closure plans, reinforcing the principle that development in fragile ecosystems must proceed only under strict expert oversight and precautionary limits.
V. The 2025 Aravalli Definition Controversy
The controversy arose from differing definitions of what constitutes the Aravalli Hills. Rajasthan adopted a landform based definition grounded in ecological connectivity, treating hills, slopes, valleys and buffers as a single system and automatically excluding core ecological areas from mining. Similarly, the Forest Survey of India in 2010 proposed a slope based definition recognising the Aravalli as a continuous ecological barrier. However, in November 2025, the Supreme Court decided to define the Aravalli Hills based only on their height specifically, hills that rise more than 100 metres above the surrounding land. Earlier definitions, like those from Rajasthan and the Forest Survey of India, had been functional or ecological, considering factors like slope, connectivity, groundwater recharge, wildlife corridors, and overall ecological importance.
The criticism is that this height-based definition ignores smaller hills and low ridges that, despite being less than 100 metres tall, are ecologically important for example, they help recharge groundwater, act as windbreaks, and maintain habitat connectivity. So, the ruling could exclude many ecologically vital areas from protection, even though they are essential to the Aravalli ecosystem.
Quantitative, Ecological and Procedural Concerns
Environmental groups argued that the 100 metre threshold excluded the majority of Aravalli landforms that perform crucial ecological functions such as groundwater recharge and desertification control. A disputed internal assessment suggested that only about 8.7% of documented hills met the threshold, a figure later denied but referred to by the Court itself. In December 2025, a coordinate Bench stayed the judgment and referred the matter to an expert committee, raising both ecological and institutional questions about consistency and judicial process.
VI. Precautionary Principle and the 100 Metre Threshold
The elevation based definition raises concerns under all three limbs of the Precautionary Principle. It risks failing to anticipate environmental degradation by excluding ecologically integral low relief features, relies on scientific uncertainty to justify regulatory relaxation, and reduces the zone within which developers must demonstrate environmental safety. This shift potentially favours mining interests and weakens the precautionary structure established in earlier Aravalli cases.
Interaction with Ex Post Facto Environmental Clearances
These concerns are intensified by the Court's contemporaneous acceptance of ex post facto environmental clearances and mineral exemptions in late 2025. Allowing retrospective approvals, particularly in a redefined and narrowed Aravalli region, undermines prior environmental assessment and reverses the burden of proof, which has historically been placed on developers. Judicial dissent has described this approach as a regression from established precautionary jurisprudence.
Conclusion
Although the Rio Declaration on Environment and Development 1992 is non-binding under international law, it has exerted significant normative influence and has been expressly relied upon by the Supreme Court of India in interpreting the environmental dimension of Article 21, most notably in Vellore Citizens' Welfare Forum v. Union of India 1996. While India was under no strict international obligation to incorporate the precautionary principle into every legislative or executive measure, the Supreme Court has internalised it through constitutional interpretation, tracing it to Articles 21, 47, 48A, and 51A(g). In this way, the principle has become a binding normative standard within Indian environmental governance, and any dilution or omission of it in ecologically fragile areas such as the Aravallis remains open to legitimate constitutional and jurisprudential critique.
In short:
- This principle being non-binding softens international law criticism,
- But does not shield the Aravalli governance framework from domestic constitutional critique, especially given settled Supreme Court precedent.
The Supreme Court of India has recognized the Precautionary Principle as part of Indian law, from Articles 21, 47, 48-A and 51 [A(g)] of the Constitution. This principle establishes three key requirements:
- Environmental protection measures must be proactive they must foresee and prevent environmental harm by addressing its root causes, instead of merely reacting to damage after it occurs.
- Absence of complete scientific proof cannot be used as a reason to delay taking preventive action against potential environmental harm.
- The onus is on the project proponent or developer to demonstrate that their proposed activity will not harm the environment, rather than on objectors to prove it will cause harm.
This doctrinal framework, crystallised in Vellore Citizens' Welfare Forum v. Union of India (1996), M.C. Mehta v. Kamal Nath (1997), and reiterated in the later orders in T.N. Godavarman Thirumulpad, directly bears upon the governance of the Aravalli Hills one of India's most critical yet fragile ecological systems.
Footnotes
1. Precautionary principle | Environmental Protection, Risk Management & Sustainability | Britannica
2. The Precautionary Principle | International Institute for Sustainable Development
3. Detailed review of implementation of the Rio Principles December 2011 DRAFT Study prepared by the Stakeholder Forum for a Sustainable Future
4. Pollution, Flood, Water Crisis: Environmentalist On Supreme Court's Aravalli Order
7. https://indiankanoon.org/doc/69408974/
8. Vellore Citizens Welfare Forum Vs Union of India . - Legal Authority
9. M.C. Mehta vs Kamal Nath & Ors on 13 December, 1996
10. https://indiankanoon.org/doc/1512135/
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