Aravalli Range & Dust Storm in Northwest of India

Why in News?

A massive dust storm swept through Rajasthan's Churu district recently, shrouding the sky in dust and turning day into night.

• Origin - These pre-monsoon convective dust storms locally termed, Andhi are driven by intense solar heating during peak summer.
• This extreme heating creates low-pressure centers over the Thar Desert, inducing highly unstable convective updrafts that lift loose, dry desert topsoil into the upper atmosphere.
• Impacted Areas - Primarily Western and Northern Rajasthan (Churu, Bikaner, Jaisalmer, Sri Ganganagar).
• Due to high-velocity winds, the dust plume regularly spills over into neighboring Haryana, Punjab, and the National Capital Region (NCR).

Aravalli range

• The Aravalli Range acting as a structural barrier between the arid Thar Desert and the fertile Indo-Gangetic Plains.
• Physical Shield - The SW-NE alignment of the Aravalli hills physically blocks lower-tropospheric desert dust from moving eastward into the fertile agricultural belt of the Gangetic Plains.
• Monsoon Interception - The range acts as a climatic divide.
• While it runs parallel to the Arabian Sea branch of the Southwest Monsoon (causing Western Rajasthan to remain a rain-shadow zone), its eastern slopes intercept moisture, keeping the Gangetic basin fertile.
• Degradation of the Aravalli Range- The protective capacity of the Aravallis is actively degrading due to human-induced factors.
  • Rocky Gap Expansion - The Aravalli Range is highly fragmented, featuring at least 28 documented natural gaps.
  • Massive illegal mining and hill flattening have widened these gaps, creating wind-conduits that allow Thar dust storms to easily breach into Delhi-NCR and Western UP.
  • Loss of Green Cover - Severe deforestation and unplanned urbanization along the foothills have destroyed the vegetative "green wall" that historically anchored shifting sand dunes.
  • Desertification - The weakening of this barrier accelerates the eastward creep of the Thar Desert, threatening the food security of the Indo-Gangetic plains by degrading soil quality and reducing visibility across Northern India.

Reference

The Indian Express | Churu dust storm