Aravalli Range:
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Location:
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They stretch for a distance of about 720 km from Himmatnagar in Gujarat to Delhi, spanning Haryana, Rajasthan, Gujarat, and Delhi.
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Formation:
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The Aravallis date back to millions of years when a pre-Indian subcontinent collided with the mainland Eurasian Plate.
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Age:
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Carbon dating has shown that copper and other metals mined in the ranges date back to at least the 5th century BC.
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Characteristics:
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The Aravallis of Northwestern India, one of the oldest fold mountains of the world, now form residual mountains with an elevation of 300m to 900m.
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Guru Shikhar Peak on Mount Abu is the highest peak in the Aravalli Range (1,722 m).
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It has been formed primarily of folded crust, when two convergent plates move towards each other by the process called orogenic movement.
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Extension:
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The mountains are divided into two main ranges – the Sambhar Sirohi Range and the Sambhar Khetri Range in Rajasthan, where their extension is about 560 km.
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The hidden limb of the Aravallis that extends from Delhi to Haridwar creates a divide between the drainage of rivers of the Ganga and the Indus.
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Their Significance:
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Checks Desertification:
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The Aravallis act as a barrier between the fertile plains in the east and the sandy desert in the west.
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Historically, it is said that the Aravalli range checked the spread of the Thar desert towards the Indo-Gangetic plains, serving as a catchment of rivers and plains.
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Rich in Biodiversity:
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Provides habitat to 300 native plant species, 120 bird species and many exclusive animals like the jackal and mongoose.
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Impacts Climate:
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Aravallis have an impact upon the climate of northwest India and beyond.
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During monsoons, it provides a barrier and monsoon clouds move eastwards towards Shimla and Nainital, thus helping nurture the sub-Himalayan rivers and feeding the north Indian plains.
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In the winter months, it protects the fertile alluvial river valleys from the cold westerly winds from Central Asia.
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Recharges Groundwater:
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Aravallis also functions as a groundwater recharge zone for the regions around that absorb rainwater and revive the groundwater level.
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Checks Pollution:
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This range is considered the “lungs” for the polluted air of Delhi–National Capital Region (NCR).
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For Haryana, having the lowest forest cover at around 3.59% of the total forest cover in India, the Aravalli range is the only saving grace, providing the major portion of its forest cover (2017 Report).
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Threats:
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The Aravalli hills are an ecologically sensitive zone but have for years borne the brunt of quarrying and environmental degradation.
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A 2018 report by a Supreme Court-appointed Central Empowered Committee (CEC) found out that 25% of the Aravalli range has been lost due to illegal mining in Rajasthan since 1967-68.
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The consequences of the mining has been a destruction of aquifers and deforestation. Many rivers originating in the Aravalli like Banas, Luni, Sahibi and Sakhi, are now dead.
Steps Taken:
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Mining in the Aravalli region has been banned since 2002 under the Supreme Court orders, unless expressly permitted by the Union Environment Ministry. However, mining continues illegally.
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The green wall is being planned from Porbandar to Panipat which will help in restoring degraded land through afforestation along the Aravali hill range.
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Residents along with volunteers from iamgurgaon, a citizen action group involved in the conservation of the Aravallis, were assisted by ecologists to create a self-sustaining Aravalli. This society driven model could be more effective to combat the degradation.