The Aravalli hills, one of the oldest mountain ranges in the world, have long been at the centre of intense legal, environmental and political debate in India. Over the years, courts have repeatedly intervened to protect this fragile ecosystem from rampant mining and unchecked development, recognising its critical role in maintaining ecological balance across northwestern India.
A key point of contention has been how the Aravalli hills should be defined for the purpose of regulation and protection. While recent decisions have revived the controversial 100-metre height benchmark, earlier judicial orders had taken a far more scientific and expansive approach to identifying and safeguarding the hill range.
The contrast between the Supreme Court’s current stance and its position in 2010 highlights how environmental governance, expert assessments and policy priorities have evolved — and, according to critics, regressed — over the past decade and a half.
Supreme Court Rejected 100 Metre Definition In 2010
In 2010, the Supreme Court firmly rejected Rajasthan’s attempt to define the Aravalli hills solely based on a 100-metre height above ground level. The court noted that such a narrow definition would exclude vast portions of the hill range and undermine efforts to regulate mining activities.
The apex court observed that limiting the Aravallis to peaks or portions rising more than 100 metres would ignore the geological and ecological reality of the range, which includes slopes, plateaus and interconnected hill systems.
This rejection marked a crucial moment in the legal history of the Aravallis, as the court chose scientific assessment over administrative convenience.
Forest Survey Of India Ordered To Conduct Assessment
To arrive at a more accurate and holistic definition, the Supreme Court directed the Forest Survey of India to conduct a detailed assessment of the Aravalli hills in Rajasthan. The court explicitly stated that the survey should not be confined to peaks or parts of hills above the 100-metre mark.
The FSI was asked to use satellite imagery and work in coordination with the Central Empowered Committee and the Rajasthan government. This collaboration aimed to ensure that the entire hill range was mapped comprehensively.
The order underscored the court’s concern over ecological degradation caused by years of large-scale mining in the region.
FSI Introduced The 3 Degree Slope Norm
Following the Supreme Court’s direction, the FSI analysed spatial terrain data and identified slope as a more reliable indicator of hill formations. The study concluded that terrain with slopes of three degrees or more was consistently associated with hills rather than flat land.
This scientific approach moved beyond simplistic height measurements and focused on the physical characteristics of the landscape. The three-degree slope norm was found to capture the true extent of the Aravalli hills far more accurately.
The methodology was widely seen as a significant step forward in environmental mapping and regulation.
Minimum Elevation And Buffer Zones Defined
The assessment further established that areas at or above an elevation of 115 metres from mean sea level — the minimum elevation of Aravalli hill districts in Rajasthan — should be considered for delineation.
All land parcels with a slope of three degrees or more within this elevation range were classified as hills. In addition, a uniform 100-metre buffer zone was added on the downhill side to protect the integrity of these formations.
This buffer ensured that mining or construction activities near the hills would not destabilise slopes or damage surrounding ecosystems.
Flat Areas And Valleys Also Included
Importantly, the FSI methodology did not exclude flat areas, tabletops, depressions or valleys that fell within the defined hill system. These features were included as integral parts of the Aravalli landscape.
This inclusive approach recognised that hill ecosystems function as interconnected units rather than isolated peaks. Disturbance in one part can have cascading effects across the entire range.
Environmental experts hailed this definition as one of the most comprehensive attempts to scientifically map the Aravallis.
Over 40,000 Sq Km Identified As Aravallis
Using the slope-based criteria, the FSI identified approximately 40,481 square kilometres across 15 districts of Rajasthan as part of the Aravalli hill system.
This finding revealed the vast extent of the range and highlighted how much of it would have remained unprotected under the narrow 100-metre height rule.
The data strengthened the case for stricter regulation and enforcement against illegal mining activities.
CEC Warned Of Ecological Destruction
The Central Empowered Committee repeatedly warned the Supreme Court about the ecological damage caused by years of unregulated mining in the Aravallis.
The court noted that large-scale extraction had led to severe ecological imbalance and that several parts of the hill range had already been destroyed.
These warnings reinforced the urgency of implementing the scientifically derived definition proposed by the FSI.
Disappearing Hills Raised Alarm
Ground verification exercises conducted later painted an even grimmer picture. Out of 128 hills sampled in Rajasthan, 31 were found to have disappeared completely due to mining and degradation.
The Supreme Court expressed deep concern over these findings, questioning how entire hills could vanish without accountability.
The observations highlighted the irreversible consequences of weak environmental enforcement.
Renewed Efforts For Common Definition In 2024
When the Supreme Court revisited the Aravalli issue in 2024, it sought a common definition applicable across Rajasthan, Haryana, Gujarat and Delhi.
The FSI and CEC were once again included in the process, with the FSI leading a technical sub-committee alongside other scientific agencies.
This raised expectations that the slope-based scientific approach would be reaffirmed.
Return Of The 100 Metre Benchmark
Despite expert input and dissenting views, the Union environment ministry informed the court that the Aravalli states had agreed to retain the 100-metre elevation criterion from local ground level.
This marked a sharp departure from the detailed scientific framework developed over the previous decade.
Critics argue that this decision effectively nullified more than 15 years of judicial oversight and environmental safeguards.
Concerns Over Environmental Impact
Environmentalists warn that reverting to the 100-metre definition could open vast areas of the Aravallis to mining and development.
The move is seen as prioritising administrative simplicity over ecological science, potentially accelerating degradation of an already fragile ecosystem.
The Aravalli hills play a vital role in groundwater recharge, climate regulation and preventing desertification.
A Turning Point For Aravalli Protection
The contrast between the Supreme Court’s 2010 rejection of the 100-metre rule and its recent acceptance underscores a significant shift in approach.
For many observers, it raises difficult questions about the future of environmental jurisprudence and the weight given to scientific expertise.
As debates continue, the fate of the Aravalli hills remains a powerful symbol of the ongoing struggle between development and conservation in India.
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