Answer

Introduction

The Supreme Court’s recent acceptance of the Environment Ministry’s (committee) recommendation, which defines the Aravalli hills as landforms rising 100 meters or more above local relief, has severely narrowed protection. This threshold may exclude over 90% of the range’s ecologically vital low ridges and scrublands, facilitating widespread mining and encroachment that escalates environmental degradation in the Delhi-NCR region.

Body

How Fragmentation Worsens Delhi’s Air Pollution

• Dust Generation: Clearing hills and vegetation exposes bare soil that becomes a source of dust, elevating particulate pollution across Delhi.
• Loss of Green Cover: Deforestation in low ridges reduces vegetative filtering of pollutants and airborne dust.
• Reduced Buffer Against Dust Entry: With hills broken up, desert-dust from adjoining arid zones can enter more easily into Delhi’s basin, compounding air pollution.
• Increased Local Emissions Concentration: Low elevation areas converted for settlement or industry trap emissions under poor ventilation, worsening smog episodes.

How Fragmentation Worsens Groundwater Stress

• Impaired Groundwater Recharge: Hill slopes and natural ground absorb and percolate rainwater; removal disrupts recharge zones lowering water tables.
• Runoff Escalation: Without vegetated slopes, rainfall runs off quickly causing less absorption, increasing flood risk and reducing groundwater infiltration.
• Contaminated Recharge: Encroachments often bring waste or pollutants that can leach into aquifers subsequently degrading groundwater quality.
• Shrinking Water Catchments: Loss of hill-based catchments reduces local springs and traditional wells, increasing dependence on distant groundwater sources.

How Fragmentation Amplifies Extreme Heat

• Loss of Vegetative Cooling: Removed tree cover and vegetation cut evapotranspiration and shade, raising land and ambient temperatures.
• Heat-Island Effects in New Settlements: Converted low-hills for urbanisation increase concrete surfaces, trapping heat and increasing localised urban heat island effect.
• Reduced Wind Buffer: Hills once directed winds and moderated temperature; fragmentation removes this barrier leading to stagnant, hotter air.
• Soil Degradation & Darker Surfaces: Exposed soils and paved land absorb more solar radiation, heating surrounding areas more than vegetated hillsides.

Aravallis as Barrier Against Desert Expansion

• Natural Green Belt: Intact hills and vegetation act like a barrier stopping desert-sand advance from adjoining arid zones toward Delhi.
• Soil and Moisture Retention: Aravalli soils and shrub-woodlands hold moisture and prevent saline-sand spread, protecting hinterland ecology.
• Climatic Buffering: They stabilize micro-climate, moderate dust movement, and prevent infiltration of arid-zone extremes toward urban areas.
• Ecological Continuity: Continuous hills support flora and fauna adapted to semi-arid ecosystems  while fragmentation breaks this continuity, facilitating desert-like degradation.

Conclusion

Narrowing Aravalli protection via the 100-metre rule jeopardizes critical environmental services — air filtration, groundwater recharge, heat mitigation, and desert-expansion prevention. Only restored, continuous hill protection and strict regulation can preserve this lifeline for Delhi’s climate and water security.

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