Measured Heights

Few landscapes in India are as old or as politically vulnerable as the Aravallis. Formed over a billion years ago, these weathered hills once acted as a geological spine across western India, arresting the march of the Thar Desert and nurturing groundwater, forests and settlements from Gujarat to Delhi. This month, they have become the latest battleground in India’s long war between conservation and development, after the Supreme Court accepted a new, government-backed definition of what constitutes an Aravalli hill.

Under the revised formulation, an Aravalli hill is any landform rising at least 100 metres above the surrounding terrain. Two or more such elevations within 500 metres of each other, along with the land between them, are to be treated as a range. On paper, the definition promises clarity. In practice, it has ignited protests across northern India and unease among ecologists who see a complex natural system being reduced to a ruler and a contour line.

The federal government insists that the change is administrative. A uniform definition, it argues, will strengthen regulation rather than dilute it. Officials deny that the new threshold opens the floodgates to mining or real-estate development. Protected forests, eco-sensitive zones and wetlands remain inviolate; new mining leases within the Aravalli range are prohibited; and even outside core areas, mining is subject to environmental clearance and ‘sustainable’ norms. Environment Minister Bhupender Yadav has stressed that only around two percent of the Aravalli system spread over roughly 147,000 square kilometres could ever be considered for mining, and only after detailed scrutiny.

Yet the anxiety runs deeper than percentages. Environmentalists argue that defining the Aravallis by height alone misunderstands what makes them valuable in the first place. Much of the range today consists not of dramatic peaks but of low, scrub-covered outcrops that play an outsized ecological role. These modest hills slow desertification, recharge aquifers, regulate microclimates and sustain pastoral livelihoods. To strip them of legal recognition because they lack vertical ambition is, critics say, to protect the silhouette while erasing the substance.

Globally, mountain systems are rarely defined by arbitrary elevation thresholds. The Andes, the Alps or the Appalachians are recognised by their geological continuity, ecological functions and climatic influence. The Aravallis are no different. They are a living system that buffers India’s most arid regions from becoming uninhabitable. Any definition that ignores geology, wildlife corridors and climate resilience risks fracturing that system into administratively convenient but ecologically meaningless parcels.

Mining bans in the Aravallis have been routinely flouted in the past, particularly in Haryana and Rajasthan, where illegal quarrying has scarred hills and drained water tables. Against that history, assurances of restraint are met with scepticism.

Activists are calling for a scientific definition that maps the Aravallis as a geological formation, recognises their ecological functions and accounts for their role in climate adaptation. Such an approach would be messier than a height-based rule, but also truer to reality.