Why a Legal Definition of the Aravallis Has Become a Flashpoint for Ecology

The Supreme Court defines Aravalli hills by a 100-metre height criterion and pauses new mining leases pending a unified plan. The ruling aims to streamline regulation and monitoring across Gujarat, Rajasthan, Haryana and Delhi, while raising concerns about environmental protection and water security in the region.

A recent Supreme Court order on the legal definition of the Aravalli hills has set off intense debate across north-western India. The court has accepted a new height-based formula to identify which landforms count as Aravalli hills, and ordered a halt on final clearances for new mining leases while a scientific and management plan is drawn up.

The ruling is intended to create uniform rules for environmental regulation and mining across Gujarat, Rajasthan, Haryana and Delhi. However, environmentalists, scientists, opposition parties and several local groups argue that the new criteria could strip protection from large parts of this fragile landscape, with serious consequences for water security, climate resilience and pollution control in the region.

Supreme Court order on Aravalli hills and new legal definition

Under the definition accepted by the Supreme Court, only landforms rising at least 100 metres above the surrounding area will be treated in law as Aravalli hills. A “range” will mean two or more such hills lying within 500 metres of each other. The court has also directed the Centre and states not to issue final approvals for new mining leases in the Aravalli region until a comprehensive plan is prepared.

Officials say the order is meant to streamline rules, curb illegal extraction and allow more predictable use of mineral resources in the Aravalli hills. The Supreme Court has asked governments to mark strict no-go zones, improve monitoring and rely on tools like satellite images and drone surveys to detect and prevent environmental violations linked to mining and construction.

Ecological and hydrological role of Aravalli hills

The Aravalli hills act as a natural defence against the spread of the Thar desert towards the east. They influence wind flow, block dust storms and aid groundwater recharge through their fractured rock formations. Many important rivers begin here, including the Luni, Sabarmati and Banas, and the landscape supports forests, grasslands and scrub that host leopards, hyenas, nilgai and many bird species.

For the Delhi-NCR region, the Aravalli hills serve as a crucial ecological buffer. The hills help reduce air pollution, soften temperature extremes and maintain local rainfall patterns. Environmental researchers warn that further loss of Aravalli cover could worsen heatwaves, weaken rainfall and deepen long-term water shortages in already stressed districts of Haryana, Rajasthan, Gujarat and the national capital region.

Geology, age and spread of Aravalli hills

The Aravalli hills run for around 670 km from south-west to north-east, cutting across Gujarat, Rajasthan, Haryana and Delhi. Geologists estimate that this mountain system is more than 2.5 billion years old, far older than the Himalayas. Erosion over vast periods has worn down once high peaks into low hills, ridges and rocky mounds that still shape the region’s ecology and geology.

Mining, urban growth and legal disputes around Aravalli hills

The Aravalli hills contain minerals such as limestone, marble, quartzite and copper, which have attracted mining for decades. Activists say that uncontrolled and sometimes illegal mining, along with expanding cities and new infrastructure projects, has damaged large stretches of the range. They accuse several state governments of using ambiguous legal definitions to allow quarrying and real estate work in ecologically sensitive zones.

Earlier, each state applied its own criteria to decide whether a particular area formed part of the Aravalli hills. This lack of a shared definition created uncertainty about which lands were eligible for protection. In some cases, mining leases were cleared by claiming that linked ridges or rocky outcrops were not technically hills or forests, even when they were connected to the wider Aravalli system.

Criticism of the 100-metre rule for Aravalli hills

Environmental groups argue that the 100-metre height rule ignores how the Aravalli hills function as an ecological system. Studies by the Forest Survey of India and independent scientists show that large parts of the range include low ridges and hillocks that rise less than 100 metres. These smaller features still play a vital role in groundwater recharge, wildlife movement and local climate control.

Critics say that, if these low formations no longer count as Aravalli hills in law, they may lose existing protection. Campaigners fear that such areas could then be opened for fresh mining, housing projects and new roads. Protests have already been reported in Rajasthan and Haryana, where local communities link the possible loss of these landscapes to worsening desertification, shrinking forests and more frequent intense heat.

Political responses and governance questions on Aravalli hills

Opposition parties allege that the revised definition of Aravalli hills will favour mining and real estate interests over environmental safety. They argue that the move weakens years of conservation work and clashes with the precautionary principle that guides much of India’s environmental law. The Union government counters that the order is being misunderstood and says that genuine forests and notified protected areas will keep their legal safeguards.

The dispute has highlighted a deeper challenge in managing landscapes like the Aravalli hills. Specialists say that ancient mountain systems cannot be judged only by height or visible shape. Their value lies in connected ridges, underlying rock structures and water systems. These extend beyond simple measurements and make it harder to fit such regions into rigid legal boxes for regulation and protection.

As climate change increases stress on water and land across north-western India, decisions on the Aravalli hills will matter far beyond the mining sector. Millions of people in Rajasthan, Haryana, Gujarat and Delhi depend on this range for groundwater, cleaner air and some protection from extreme weather. The Supreme Court’s intervention could either strengthen long-term safeguards through clearer rules or reduce them by narrowing what legally counts as the Aravalli hills.