The Aravalli Range is one of the world’s oldest fold mountain systems, running approximately 692 kilometers across northwestern India from Delhi, through Haryana and Rajasthan, to Gujarat. It acts as a critical geographic and climatic divide between the arid Thar Desert to its west and the more fertile Northern Plains and Malwa Plateau to its east.
Role as a Climatic Divide and the Thar Desert Creation
The Aravallis play a decisive role in shaping the precipitation patterns of northwestern India. The range aligns parallel to the direction of the southwest monsoon’s Arabian Sea branch. Because the mountains do not cross or obstruct these moisture-laden winds, the clouds pass over the region without being forced to lift and condense, depriving western Rajasthan of orographic rainfall. Conversely, the Aravallis act as a barrier to the Bay of Bengal branch of the southwest monsoon. The eastern slopes receive moderate rainfall, supporting agriculture and vegetation, while the western side remains in a rain-shadow zone, accelerating desertification and establishing the hyper-arid environment of the Thar Desert.
| Parameter | Western Side (Thar Desert) | Eastern Side (Semi-Arid to Sub-Humid Plains) |
| Topography | Sand dunes, barchans, rocky hammadas | Fertile alluvial plains, rolling hills, river basins |
| Average Rainfall | Less than 15 cm to 40 cm annually | 60 cm to 100 cm annually |
| Drainage System | Ephemeral and inland drainage (e.g., Luni River) | Perennial and semi-perennial rivers (e.g., Banas, Chambal tributaries) |
| Soil Profile | Aridisols and Entisols (Sandy, saline, low organic matter) | Alfisols and Inceptisols (Alluvial, loamy, fertile) |
Impact on Regional Drainage and Hydrology
The Aravalli Range serves as a major hydrological watershed separating the drainage systems of the Arabian Sea and the Bay of Bengal.
Western Drainage System (Desert Hydrology)
Rivers originating on the western slopes of the Aravallis flow into the arid tracts of the Thar Desert. The Luni River is the most prominent river of this system. It originates in the Pushkar Valley near Ajmer and flows southwest into the Rann of Kutch. It is ephemeral and turns increasingly saline downstream of Balotra. Other minor seasonal streams include the Sukri, Jawai, and Bandi.
Eastern Drainage System (Plains Hydrology)
The eastern slopes give rise to rivers that feed into the Yamuna-Ganga system. The Banas River, a major tributary of the Chambal River, originates in the Khamnor hills of the Aravalli Range. This system ensures sustained alluvium deposition in the northern and eastern plains of Rajasthan, preventing desert conditions from expanding eastward.
Prevention of Desertification and the “Green Wall” Concept
The Aravalli Range acts as a natural geomorphological wall that blocks the eastward march of the Thar Desert toward the fertile Indo-Gangetic plains. Wind erosion in the Thar Desert creates loose, shifting sand dunes that are carried eastward by strong summer winds.
The Threat of Breaches
Geological studies indicate that due to illegal mining, deforestation, and urbanization, several gaps have emerged across the Aravalli Range. These gaps act as conduits through which desert sand penetrates into Haryana, Delhi, and western Uttar Pradesh.
Great Green Wall of Aravalli
To counter this, ecological initiatives have been planned to create a 1,400 km long and 5 km wide green ecological corridor from Gujarat to Delhi along the Aravalli range. This buffer zone aims to restore degraded forest covers, bind the soil, and halt dust storms and desert expansion.
Soil and Geomorphological Distinctions
The Aravallis divide northwestern India into two distinct physiographic units under the North-Western Landforms classification.
Marusthali and Bagar (West)
The region immediately west of the Aravallis is the Bagar, a semi-arid transitional plain consisting of grass steppes and patches of fertile land called Rohi. Further west lies the Marusthali, the core desert region dominated by shifting sand dunes (Dhrian) and longitudinal dunes.
Rajasthan Plains (East)
The eastern side comprises the Mewar plains and the Chhappan plains, characterized by fertile regular alluvial deposits, higher water tables, and extensive cultivation.
Mineral Wealth and Economic Relevance
The Aravalli Range is composed of ancient Archean and Proterozoic rocks belonging to the Aravalli and Delhi Supergroups. These formations are highly mineralized, impacting the economic geography of the surrounding plains.
Metallic Minerals
The range holds India’s largest reserves of lead-zinc ores (Zawar mines, Udaipur), silver, and copper (Khetri copper belt, Jhunjhunu).
Non-Metallic Minerals
It is an abundant source of high-quality marble (Makrana), granite, limestone, and gypsum, which heavily drive the construction industries across the Northern Plains.
Significant Facts and Trivia for Civil Services Examination
Ancient Fold Mountains
The Aravallis are classified as residual fold mountains. They were formed during the Proterozoic era through geosynclinal folding, making them older than the Himalayan mountain system.
Guru Shikhar
The highest peak of the Aravalli Range is Guru Shikhar, located on Mount Abu at an altitude of 1,722 meters above sea level. It hosts the famous Dilwara Jain Temples and acts as a micro-climatic island within the semi-arid region.
Inland Saline Lakes
The depression areas between the Aravalli spurs and the desert plains house prominent inland saline lakes, such as Sambhar Lake (India’s largest inland salt lake), Didwana, and Pachpadra. These lakes are remnants of the ancient Tethys Sea or are formed due to capillary action concentrating salt in endorheic basins.
National Parks and Wildlife Sanctuaries
The Aravalli ecosystem encompasses critical conservation zones including the Sariska Tiger Reserve (Alwar), Ranthambore National Park (at the junction of Aravalli and Vindhya ranges), Kumbhalgarh Wildlife Sanctuary, and Mount Abu Sanctuary.
Last Modified: June 4, 2026