Context:

• The debate over defining the extent of the Aravalli Range has resurfaced following directions from the Supreme Court of India to evolve a uniform definition.
• A new expert committee is being constituted after the Court stayed its (November 2025) judgment amid environmental concerns.
• The issue holds immense ecological significance, as the Aravallis act as a natural barrier against desertification, support biodiversity, and sustain groundwater systems in north-west India.

Background:

• Earlier mapping efforts - FSI’s scientific mapping (2011):
  • The Forest Survey of India (FSI), following a 2010 SC order, undertook independent mapping of the Aravalli hills across 15 districts of Rajasthan.
  • Using Survey of India topographic sheets (1:50,000 scale) and GIS-based analysis, FSI -
    • Digitised contours painstakingly.
    • Applied a 3-degree slope criterion to delineate hills.
  • The final map was submitted (in April 2011), forming a scientifically robust baseline.
• Recent developments:
  • Committee-based redefinition (2024–25):
    • A committee of secretaries proposed a 100-metre elevation criterion for defining the Aravallis.
    • The report (October 2025) significantly reduced the geographical spread of Aravalli hills from FSI’s 62 districts to only 37 districts.
  • Judicial intervention:
    • The SC’s (November 2025) judgment triggered protests by environmentalists.
    • The SC (in November 2025) accepted a new, restrictive definition of the Aravalli hills—defining them as only those with a height of/over 100 meters or clusters of such hills within 500 meters.
    • This move is criticized for potentially leaving smaller hills vulnerable to mining.
    • Later (December 2025), the SC stayed its own judgment, and ordered formation of a new expert committee

Core Issue - Elevation vs Slope-Based Definition:

• Problems with 100 m elevation criterion:
  • It is an arbitrary benchmark, which ignores geomorphological continuity.
  • It excludes low-lying hills, constituting many ecologically critical areas that fall below 100 m.
  • This endangers fragmentation of landscape, and breaks ecological connectivity.
• Strength of 3-degree slope criterion (used by FSI in 2011):
  • Captures actual terrain characteristics (terrain continuity and ecological integrity)
  • Ensures continuity of hill systems
  • Based on field-tested GIS analysis

Key Concerns Raised:

• Large-scale exclusion of districts: Important districts like Sawai Madhopur and Chittorgarh excluded despite inclusion in Aravalli Green Wall Project, and recognition under UNESCO’s Hill Forts of Rajasthan.
• Policy inconsistency across agencies: Multiple agencies recognize the broader Aravalli extent. For example, the Ministry of Environment, Ministry of Culture, Central Ground Water Board, Geological Survey of India.
• Ecological risks:
  • Rajasthan has only ~8% forest and tree cover (ISFR 2023), and majority of this lies within the Aravalli region.
  • Hence, misclassification may lead to mining expansion, deforestation, groundwater depletion, and desertification (Thar expansion).

Key Challenges:

• Scientific challenges: Lack of consensus on definitional criteria, risk of discarding legacy datasets (2011 mapping).
• Administrative challenges: Inter-agency inconsistency, pressure from development and mining interests.
• Legal challenges: Frequent judicial interventions leading to policy uncertainty.
• Environmental challenges: Fragile ecosystem with low forest cover. High vulnerability to climate change and land degradation.

Way Forward:

• Adopt scientific and tested criteria: Re-evaluate and possibly retain the 3-degree slope method, avoid arbitrary elevation-based definitions.
• Use existing high-quality data: Retain Survey of India-based datasets (2011), ensure continuity in methodology.
• Inter-agency harmonisation: Align definitions across the Environment Ministry, cultural and geological bodies.
• Precautionary principle: In case of doubt, adopt broader inclusion to protect ecology.
• Independent expert review: New committee should include GIS experts, ecologists, and geomorphologists.
• Strengthen legal safeguards: Clear, enforceable definition to regulate mining, land use change.

Conclusion:

• The debate on defining the Aravallis is not merely technical—it is a test of India’s commitment to evidence-based environmental governance.
• Discarding scientifically evolved methodologies in favour of arbitrary thresholds risks irreversible ecological damage.
• A balanced approach, grounded in scientific rigour, institutional memory, and ecological prudence, is essential to preserve this old mountain system for future generations.