A new definition of what constitutes the Aravali Hills has triggered concern among environmental experts, who warn that large portions of the ancient mountain range may lose protection and become vulnerable to mining and development. The government’s decision, recently accepted by the Supreme Court, classifies only hills with an elevation of more than 100 metres as part of the Aravalis. Specialists say this narrow criterion could “erase” much of the landscape that currently acts as a natural barrier for North India.
The Aravalis stretch roughly 700 kilometres, forming one of the oldest mountain systems in the world and playing a crucial role in blocking desert dust, recharging groundwater and providing biodiversity corridors. Environmental scientists say that limiting protection to elevations above 100 metres fails to recognise the ecological value of low-lying ridges, gentle slopes and connected landforms that together make up the Aravali system.
Climate researcher Harjeet Singh of the Satat Sampada Climate Foundation expressed disappointment at the court’s decision, arguing that the new definition could trigger “slow deletion” of the mountain chain. He said that the change on paper may be described as “sustainable mining” or “development,” but in practice it could lead to blasting, road construction and deep pits through areas that serve as wildlife corridors and village commons.
Environmental groups warn that these changes could increase dust storms, reduce groundwater levels and worsen Delhi-NCR’s already severe air pollution. Specialists have emphasised that the Aravalis act as a green shield at a time when the national capital continues to record “very poor” air quality levels. Several monitoring stations recently reported high air pollution, with the Air Quality Index climbing above 300 in multiple areas.
Under the new guidelines, “Aravali Hills” are defined as landforms at least 100 metres above their surroundings, while an “Aravali Range” is identified as clusters of two or more such hills within 500 metres of each other. Although the Supreme Court instructed authorities to mark ecologically sensitive areas where mining would be restricted, environmentalist Vimlendu Jha said this decision could still result in substantial loss of the mountain range. He warned that allowing mining or infrastructure expansion could reduce the Aravalis by up to 90 per cent.
The Aravalis hold critical ecological value. They are the source of important rivers including the Chambal, Luni and Sabarmati, and their forest and grassland ecosystems support numerous threatened species. However, decades of mining, grazing, deforestation and encroachment have accelerated soil degradation and desertification while reducing the water-holding capacity of the land.
In 2023, the government launched the Aravalli Green Wall initiative, proposing a five-kilometre-wide green belt covering 6.45 million hectares across Gujarat, Rajasthan, Haryana and Delhi. Environmental organisations support the plan but warn that the fundamental drivers of pollution and dust in the region are not being tackled effectively.
Experts are urging policymakers to reconsider the narrow definition of the hills, arguing that ecological protection should be based on environmental function rather than height. They say the outcome of the decision will shape water security, wildlife conservation and human health for millions of people, especially vulnerable populations such as children, elderly residents and outdoor workers.
Political leaders have also raised concerns. Congress leaders recently criticised amendments to the Forest Conservation Act and called for a debate in Parliament on worsening air pollution and shrinking green cover. Environmental advocates believe that revisiting the definition is essential, saying that no amount of urban plantation can compensate for the protective role of the Aravalis in North India.