Explained: Supreme Court's 100-Metre Rule, Mining Ban And What's Next For Aravallis

The Supreme Court has approved a new official definition of the Aravalli Hills, a ruling that could reshape the legal protection of one of the world's oldest mountain systems. According to a report in Business Standard, a bench on November 20 accepted recommendations submitted by a Union Environment Ministry committee that sought to standardise how the 692-km range across north-west India is defined.

Under the new criteria, any landform within Aravalli districts must have at least 100 metres of elevation above the local relief - including its slopes and adjoining areas - to be treated as part of the Aravalli Hills. The court also directed the Centre to carry out detailed scientific mapping and develop a "sustainable mining plan", and ordered that no new mining leases be issued until this work is complete.

However, the 100-metre threshold has triggered concern. Environmentalists warn the rule may exclude large stretches of low-lying but ecologically linked ridges that had previously fallen within the protective ambit. Citing The Indian Express, the court was informed that an internal Forest Survey of India (FSI) assessment found only 1,048 of 12,081 mapped hills - just 8.7% - meet the 100-metre benchmark. This could mean nearly 90% of what was commonly understood as Aravalli terrain may lose legal protection.

A legacy of judicial protection

Courts have historically played a key role in safeguarding the Aravallis. Since the 1990s, the Supreme Court has repeatedly intervened to curb unregulated mining across Rajasthan and Haryana. The landmark 1996 judgement in MC Mehta vs Union of India led to the shutdown of hundreds of quarries around Delhi after the court found mining activities were causing "irreversible environmental damage".

Subsequent orders tightened monitoring, imposed bans in ecologically sensitive zones, and directed states to rehabilitate mined areas. Over the years, courts have also pulled up state governments for illegal extraction, weak enforcement, and failure to protect crucial wildlife corridors.

This long-standing judicial oversight is one reason many conservationists fear the new definition could dilute decades of environmental safeguards.

Ecological risks flagged by experts

Scientists and conservation groups warn that reducing the legally recognised footprint of the Aravallis could accelerate ecological decline across the region. Lower ridges and connected hill systems - often the first to be encroached upon - perform essential functions:

• Habitat loss and fragmentation of wildlife corridors, affecting leopards, hyenas, and bird species
• Damage to groundwater recharge zones, affecting peri-urban farming belts
• Degradation of scrub forests and native tree cover that support reptiles, pollinators, and grassland birds
• Increased desertification risks, with dust and heat worsening air quality in the National Capital Region
• Disruption of microclimates, which could push groundwater levels further down

The Congress party too raised concerns. Congress chief Sonia Gandhi launched a sharp attack against the Centre over the change in the definition of the Aravalli hills range, calling it a "death warrant" for the hills. Party leader and former environment minister Jairam Ramesh tweeted: "This is bizarre and will have very grave environmental and public health consequences. It calls for an immediate review."

A report by a central committee, quoted by news agency PTI, underscores the Aravallis' importance in moderating the regional climate, slowing desertification, and recharging aquifers. It urges states to follow strict mapping protocols, adopt stronger safeguards, and use digital tools - including AI and machine learning - to curb illegal mining.

Now, the top court's 100-metre rule has intensified a debate around striking a balance between sustainable mining and the survival of an ancient ecological shield that has already endured decades of pressure.