Source: IE
Subject: Mapping
Context: A Forest Survey of India (FSI) assessment has revealed that the government’s new 100-metre height definition for Aravalli Hills—accepted by the Supreme Court—removes over 90% of the Aravalli landscape from protection.
About Aravalli Hills:
What It Is?
- The Aravalli Hills are one of the oldest fold mountain ranges in the world, forming a major ecological barrier, wildlife corridor, and mineral-rich region of northern and western India.
Located In: Extends from near Delhi through southern Haryana and Rajasthan to Gujarat, running roughly 670 km.
Formation:
- Formed during the Proterozoic era through ancient tectonic collisions, part of the Aravalli–Delhi orogenic belt.
- Once very high mountains, they have been heavily eroded over millions of years.
Geological & Physical Features:
- Typically, 300–900 m high, with the highest peak Guru Shikhar (1,722 m) in Mount Abu.
- Composed of quartzite, marble, granite, copper- and zinc-bearing rocks.
- Generate rivers such as Banas, Luni, Sabarmati, and Sahibi.
- Act as a major barrier preventing sand, dust, and desertification from advancing eastward.
About Aravalli definition issue:
What is the “100-metre definition” of Aravalli Hills?
- The Supreme Court has accepted a recommendation from the Environment Ministry that only those landforms that rise 100 metres or more above their immediate surroundings (local ground level) will be counted as “Aravalli Hills.”
- If a hill is less than 100 m tall (from base to peak), it is not considered Aravalli under the new rule.
- Only tall hill sections remain protected and smaller hills lose protection.
- Issues Highlighted by FSI Survey:
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- New 100-metre definition excludes 90% of hills, leaving them unprotected.
- Earlier scientific criteria (slope + 30m height) would have covered around 40%, far more than the new definition.
- Lower hills (10–30 m) are critical windbreaks that stop sand and dust from the Thar desert.
