Redefining The Aravallis: What Happens When Legal Elevations Overshadow Ecological Realities?
The Supreme Court's accepting a new legal definition of what constitutes a “hill” has implications for climate adaptation and disaster-risk management.
By Aparna Roy
Published : December 23, 2025 at 6:35 PM IST
The Aravalli Hills have long been one of India’s most important ecological assets, threading through four states and supporting water cycles, biodiversity and climate resilience across semi-arid landscapes. Recently, this ancient range has become the centre of an intense controversy after the Supreme Court accepted a new legal definition of what constitutes a “hill” in the Aravalli context — one predicated largely on elevation relative to local relief. This shift has sparked protests in Gurugram, Udaipur and beyond, with activists warning that a technical regulatory fix could unravel decades of ecological protection.
The new definition specifies that for a landform to qualify as a hill under the Aravalli framework, it must rise at least 100 metres above surrounding terrain, and that two such hills within 500 metres constitute a range. On its face, this seeks to standardise classification across multiple jurisdictions where inconsistent interpretations of the Aravallis have previously enabled unregulated mining and legal contests. Yet the fallout reveals a pressing question:
When legal definitions privilege geometric thresholds over functional ecology, what do we gain — and what do we risk losing?
Answering this requires unpacking the tension between administrative clarity and ecological function. Scientific mapping, which underpins land-use regulations, is inherently technical: it uses GIS, digital elevation models and contour surveys to chart terrain features. For policymakers, such clarity is meant to draw bright lines around protected areas and to curb the very ambiguity that has allowed mining leases to proliferate in parts of the Aravallis. But the assumption that only landforms above a discrete height threshold are ecologically significant does not align with how ecosystems operate. In the Aravalli context, even minor ridges and lower slopes — often below the 100-metre cut-off — play essential roles in modulating hydrology, stabilising soils, and sustaining vegetation patterns that trap dust and buffer extreme temperatures. These functions do not magically disappear beneath a regulatory threshold.
The ecological reality is that the Aravalli system is a continuum shaped by millions of years of geological processes, now weathered into a mosaic of hills, ridges, outcrops and plateaus. These features collectively regulate rainwater infiltration into fractured rock aquifers, which in turn sustains wells, springs and baseflows for rural communities across Rajasthan and Haryana who rely on groundwater for drinking, irrigation and livestock through dry seasons. When smaller landforms are legally derecognised, their hydrological contributions risk being disregarded in planning and protection frameworks, even if they remain physically present on the ground.
This has immediate implications for climate adaptation and disaster-risk management. Contemporary climate risk models are sensitive to landscape connectivity and surface processes. A hill that fails to meet an arbitrary height may nonetheless shape local flood pathways, influence runoff patterns, and contribute to cooler microclimates or dust suppression downwind. If legal classification leads planners to exclude these landforms from hazard maps or recharge zone designations, disaster risk assessments could be skewed, leaving communities exposed to heightened flood risk or water insecurity at a time when both are being amplified by climate change.
The tension extends to policy implementation on the ground. Proponents of the new definition note that core ecological zones and forested hills will remain protected, and that the proportion of the Aravalli landscape that may be theoretically eligible for regulated mining is extremely limited — often cited at under 0.2% of the over 1.4 lakh sq km area. They also emphasise that no new mining will be sanctioned without detailed scientific assessment. Yet such assurances do not fully mitigate the deeper structural issue: legal visibility matters. Protected status influences everything from environmental impact assessments to investment decisions and enforcement priorities. When protection is tied narrowly to elevation, significant tracts of ecologically vital land risk slipping through regulatory nets simply because they did not meet a geometric criterion.
Nowhere are these stakes clearer than in the Delhi-NCR region, where the Aravallis function as a crucial ecological buffer. These landscapes influence air quality, wind patterns and groundwater recharge — a triad of services critical to urban resilience. Fragmentation of legal protection, even if only on paper, may embolden pressures for infrastructure and real estate development on lower slopes that are still functionally part of the Aravalli system. Loss of continuity in vegetated ridges could weaken natural dust barriers and diminish recharge areas that feed aquifers under increasing extraction stress.
For rural communities that depend on rainwater percolation through fractured rocks, the consequences are tangible: deeper water tables, reduced spring flow and higher costs for water extraction. These are not hypothetical impacts but lived realities in regions where monsoonal variability and climate stress are already pronounced. The hills act as natural sponges — capturing, storing and releasing water over seasonal cycles. Disaggregating them through legal definitions risks disrupting this sponge effect.
This debate highlights a larger imperative for Indian environmental governance: to ensure that legal definitions are grounded in ecological function, not just administrative simplicity. Rather than allowing elevation alone to dictate protection status, policy frameworks should integrate metrics that reflect hydrological importance, biodiversity value, connectivity and climate resilience. Scientific mapping must encompass not only topography but also ecosystem services and social reliance on landscapes that do not necessarily rise above arbitrary lines on a map.
In the Aravallis, the path forward must avoid a simplistic reading of vertical magnitude and instead embrace a landscape perspective that recognises the ecological web woven across hills, valleys and foothills alike. As public protests, expert analyses and legal contestations unfold, the broader question remains: Can we reconcile the need for regulatory clarity with the complex, interlinked reality of ecological systems? The answer will shape not just the future of the Aravallis, but how India negotiates the persistent tension between development, law and ecology.
Disclaimer: The opinions expressed in this article are that of the writer. The facts and opinions expressed here do not reflect the views of ETV Bharat.
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