With the Delhi-NCR region grappling with severe air pollution, attention has shifted to the recent protests over the Aravallis. Environmentalists, civic groups such as People for Aravallis, scientists and opposition parties including the Congress and the Samajwadi Party say the proposed height-based definition would leave more than 90% of low-lying ridges, foothills and scrublands without strong protection.
They warn that this could open the door to increased mining, real estate projects and urban sprawl, causing irreversible damage – accelerating desertification, depleting groundwater, disrupting biodiversity and exacerbating air pollution and water scarcity across northern India.
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The Aravalli serves as a critical natural barrier to prevent the eastward spread of the Thar Desert, supports groundwater recharge for rivers like the Chambal and Luni, maintains biodiversity, and helps moderate the climate and air quality of the National Capital Region (NCR).
What is the Aravalli Hills Controversy?
In November 2025, the Supreme Court adopted a uniform legal definition of what constitutes the Aravalli Hills and the Aravalli Range on the recommendation of a committee headed by the environment ministry.
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According to this definition, “Aravalli Hill” is terrain with an elevation of at least 100 meters above the local surrounding terrain and “Aravalli Range” is a cluster of two or more such hills within 500 meters of each other.
Meanwhile, Minister for Environment, Forests and Climate Change Bhupender Yadav on Monday assured that the government is committed to keeping the hills safe.
According to the union minister, the reclassification was done to ensure uniformity in enforcement of environmental laws across states, as earlier each state had its own classification that allowed mining. Similarly, he also informed that only 0.19% of the entire range is made available for mining and no new mines are being opened. The affected area is expected to be 277.89 square kilometers, out of a total of 1.44 million square kilometers.
He also said that the definition was made stricter to protect the Green Aravalli wall.
In an interview with Mint Dr. Manish Kumar, a climate scientist with more than 10 years of experience and director of the Sustainable Bharat Foundation, a non-profit research organization, spoke about the impact of the Aravalli range on air pollution.
How does Aravalli affect air pollution in Delhi?
The Aravallis act as a natural barrier that helps limit dust transport and influences regional wind patterns. Degradation of this landscape may increase the dust load towards Delhi-NCR, especially during dry and windy conditions. Therefore, enhancing vegetation cover, regulating mining activities and restoring degraded areas in the Aravallis can support regional air quality management. While pollution in Delhi has many factors, protecting surrounding natural buffers remains an important complementary strategy.
Why are environmentalists interested?
Ecologists are primarily interested in how the ecological value will be interpreted during implementation. While the Supreme Court sought clarity and uniformity, the Aravalli ecosystem includes the lower hill systems, slopes, forests and groundwater recharge zones that are environmentally significant. The key opportunity now lies in ensuring that scientific mapping and the proposed management plan adequately capture these functional ecological components.
Why does the ecological balance of Delhi-NCR matter?
The ecological balance of Delhi-NCR is closely linked with the surrounding natural systems such as the Aravallis, forest areas and groundwater recharge zones. These systems help regulate temperature, promote water security and reduce the environmental burden caused by rapid urbanization. Incorporating ecological considerations into spatial planning and regional development strategies can significantly reduce long-term urban risks.
What are climate risks?
The Aravallis contribute to regional climate regulation by supporting vegetation cover, soil stability and groundwater systems. Their degradation can amplify climate risks such as heat stress, dust storms and declining water availability.
Why do the Aravallis matter?
The Aravalli Range is India’s oldest folded mountain belt, about 2 billion years old, which acts as a natural shield to prevent the spread of the Thar Desert eastward into the fertile Indo-Gangetic plains. By blocking hot, dry winds and sand, they retain soil moisture and prevent the desert from advancing into Haryana, Rajasthan, western Uttar Pradesh and beyond. Without this barrier, large parts of northern India could dry up, threatening agriculture and food security.
Source: Britannica.
For Delhi-NCR, one of the most polluted areas in the world, they capture dust from the Thar and absorb particles like PM2.5/PM10 and act as ‘green lungs’. Their destruction would intensify heat waves, smog and the air quality crisis.
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The fractured rocks and terrain of this range allow rainwater to seep deep and recharge aquifers that supply water to millions of people in water-stressed areas, including Delhi-NCR.
In addition, the Aravallis also coincide with India’s commitments under the United Nations Convention to Combat Desertification. Ongoing threats such as mining and urbanization have already caused significant damage, leading to soil erosion, reduced recharge and habitat loss.
The Aravalli Range is a 670 kilometer long mountain range in the northwestern part of India. The highest altitude of the mountain range was recorded at 1722 meters.
The hill starts near Delhi, passes through Haryana, Rajasthan, and ends in Gujarat. The highest peak of the range is known as Guru Shikhar at Mount Abu in Rajasthan.
(With input from agencies)
