The Aravalli Baseline Problem

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In light of the recent judgement by the Supreme Court of India on the definition of what constitutes the Aravalli, mainstream media has been busy asking doomsday questions on the consequences if they are lost forever.

These sharply worded posts channel and amplify outrage. But they imply inevitability and closure when the real-world debate and actions are still about definitions, measurement frameworks, and enforcement tools.

The result? Selective amplification of a few technical numbers, stripped of their context, and inflated into digital trenches.

A backgrounder from the Press Information Bureau (Government of India) on this matter says that it is “wrong to conclude that mining is permitted in all landforms below 100 meter height.” On account of three points:

1. The State of Rajasthan has been following this definition since 2006.
2. All the landforms enclosed within the lowest binding contour encircling Hills of height 100 meter or more irrespective of their height and slopes are excluded for the purposes of grant of mining lease.
3. Similarly, the Aravalli range has been explained as all the landforms which exist within 500 meters of two adjoining hills of height 100 meter or more. All landforms existing within this 500 meter zone irrespective of their height and slopes are excluded for the purposes of granting mining leases.

The Flashpoint: “100 Meters Above Local Relief”

At the heart of the battle lies a single sentence used by the courts to define what gets included in the Aravalli range: “Any landform located in the Aravalli districts, having an elevation of 100 meters or more from the local relief, shall be termed as Aravalli Hills.”

The key point to be understood here is that this does NOT mean:

• 100 meters above sea level, OR
• 100 meters above a fixed national benchmark

It means a landform that rises 100 meters vertically from the lowest immediately surrounding terrain. The latter subject to the decision of the experts involved.

This distinction matters. Measurement against a local relief determines a relative height, not absolute elevation.

The Problem: A Movable Baseline

The problem with ground-based “local relief” is that it does not have a fixed unbiased reference.

With enough human intervention (quarrying, excavation, road cutting, grading), the lowest surrounding terrain can be altered. Once that happens, the same physical hill can suddenly appear shorter relative to its surroundings, even though the hill itself has not changed.

In effect: to cut a hill, you just have to shift its baseline.

Protection becomes dependent not on the integrity of the hill, but on how creatively its surroundings are modified. This creates a perverse incentive structure and a measurement flaw.

A Simpler Alternative: Why Not Measure From the Top Down?

There is a straightforward way to remove this ambiguity entirely: why not measure hill integrity from the top, not from an adjustable local base.

Top-down measurement offers four decisive advantages:

1. The summit is stable; baselines are not
2. Satellite-native, not dependent on discretionary field surveys
3. Cheaper and scalable across large regions
4. Continuously monitorable, allowing easy comparison over time

This eliminates incentives to game definitions by manipulating surrounding terrain.

Governance, Infrastructure, And Environment Projects Already Do This

The idea of measuring landscapes continuously from space may sound novel, but it is not a recent development.

Several large multi-country cooperation projects — like Sentinel-1, GRACE, CryoSat, and NISAR — monitor glaciers, sea shores, land, and other surface movements precisely.

Crucially, this approach would not be a conceptual leap for India, as several flagship national programs rely on similar ideas at scale:

• Infrastructure planning under PM Gati Shakti
• Crop insurance and agricultural risk assessment
• Flood, forest, subsidence, and land-use monitoring

Satellite-derived terrain data is already trusted for money, logistics, renewable energy, and national planning. Using it for ecological protection is not radical — it is logical and maybe overdue.

Moreover, continuous monitoring through satellite monitoring provides a simple, safe way to identify illegal mining zones.

Project NISAR

The NISAR project, which entered popular media consciousness only during its recent launch, is the result of nearly two decades of joint development between NASA and ISRO.

The project was initiated in the late 2000s, during the tenure of Manmohan Singh in India and Barack Obama in the United States. It progressed steadily across successive administrations and reached deployment under Narendra Modi and Donald Trump.

NISAR is a cutting edge Earth-observation system with dual-frequency synthetic aperture radar operating in L-band and S-band, capable of detecting surface deformation at rates as small as 4 millimeters per year. The satellite completes global coverage every 12 days with a 242-kilometer imaging swath and spatial resolution between 3 to 10 meters depending on mode.

NISAR Data Is Open Source & Free

Equally important, NISAR’s data is designed to be open and publicly accessible. It does not require any new committees, new resources, or discretionary measurement choices.

At its core, NISAR uses repeat-pass interferometric radar to observe the same terrain again and again, and compares those observations to detect millimeter-to-centimeter scale surface deformation over time.

Operating from a 747-kilometer sun-synchronous orbit, it tracks changes in terrain elevation, ice mass, and surface structure with centimeter-level precision.

Crucially, its radar penetrates clouds and vegetation, enabling continuous monitoring regardless of weather or ground cover. This can be a critical advantage for regions like the Aravallis where atmospheric conditions and vegetation would otherwise limit optical satellite effectiveness.

While individual images have meter-scale spatial resolution, the strength of the system lies in change detection, not visual detail. For landscapes like the Aravalli Hills, this distinction is crucial.

Damage here rarely occurs as a single dramatic event. It accumulates gradually, often escaping notice in isolated field inspections, but becoming unmistakable when tracked as a time series.

With Aravallis spanning the jurisdiction of four state governments, several cities, and ULBs, any one of them could commission a study and protect this natural geographical heritage.

Conclusion

The capability to monitor terrain change continuously already exists; what remains is whether we choose to anchor definitions and enforcement to this physical record rather than to adjustable ground references.

Judgments can be revisited, definitions can be refined, and interpretations can evolve. But measurement frameworks, once embedded, silently shape outcomes for decades. If environmental protection depends on fixed, externally verifiable physical reality, it becomes automatic and free from polarization.

The Aravalli are not just stone quarries but a living landscape whose future can be shaped simply by how we choose to measure and preserve them.