Aravalli Range

The Aravalli Range is among the oldest mountain systems on Earth, a relict orogenic belt formed during the Proterozoic eon roughly 1.5 to 3.5 billion years ago through the collision of the Bundelkhand and Marwar cratons along the Aravalli-Delhi orogenic belt. Geologically it belongs to the class of fold mountains, but unlike the youthful Himalaya it is a deeply denuded, peneplained system whose original Himalayan-scale heights have been worn down over aeons to modest residual ridges. The range comprises rocks of the Aravalli and Delhi Supergroups — quartzites, schists, gneisses, phyllites, and marble — and is rich in mineral wealth including zinc, lead, copper, and the white marble of Makrana. For aspirants of the civil services, the Aravallis are a recurring General Studies Paper I (GS1) physiography topic, frequently examined alongside India's other peninsular and extra-peninsular relief features.

The range extends approximately 692 kilometres in a northeast-to-southwest alignment, running from Delhi in the north through Haryana and Rajasthan to terminate near Palanpur in Gujarat. Its highest peak is Guru Shikhar (1,722 metres) in the Mount Abu massif of southern Rajasthan, the only hill station in the Aravalli system and the highest point between the Himalaya and the Nilgiris in southern peninsular India. The range is conventionally divided into a northern sector — the Sambhar–Khetri belt — and a southern sector, the Sambhar–Udaipur ranges, which are higher and more continuous. In the north the Aravallis fragment into discontinuous, low ridges that pass through Alwar, Gurugram, and finally into the Delhi Ridge, where the system effectively peters out beneath the Indo-Gangetic alluvium.

The Aravallis perform a defining hydrological and climatic function. The range acts as a water divide between the inland drainage of Rajasthan and the rivers flowing toward the Arabian Sea and the Gangetic system; the Banas, Luni, Sahibi, and Sakhi originate in or are guided by the range. The eastern flank feeds the Chambal and Banas basins, while the west borders the arid Thar. Critically, the Aravallis are held to act as a green barrier checking the eastward expansion of the Thar Desert, intercepting dust-laden winds and influencing the monsoon's behaviour over the region. The Saraswati and other relict drainage systems are also associated with the range's western apron. Mineral districts such as Zawar (zinc-lead), Khetri (copper), and Makrana (marble) lie along its structural trend.

In contemporary governance the Aravallis are the subject of intense environmental litigation and policy. The Supreme Court of India, in M.C. Mehta v. Union of India and subsequent orders, repeatedly restricted mining in the Aravalli notified areas of Haryana and Rajasthan, and a 2018 order directed the demolition of illegal structures and the protection of the range against quarrying. The Haryana Aravalli zone, governed partly under the Punjab Land Preservation Act of 1900, has been a flashpoint over the 2019 amendment that conservationists argued would open the range to construction. The National Capital Region Planning Board and the Forest Survey of India track the range's depleting forest cover, while the Asola Bhatti Wildlife Sanctuary and Sariska Tiger Reserve fall within the Aravalli landscape. Rajasthan's Mount Abu and the Kumbhalgarh fort, a UNESCO World Heritage site, are perched on the range.

The Aravalli Range must be distinguished from the Western Ghats and the Vindhya Range, with which it is sometimes conflated. The Western Ghats are a block-faulted escarpment along the western edge of the Deccan plateau, far younger in their present uplifted form, whereas the Aravallis are residual fold mountains of Precambrian age. The Vindhyas and Satpuras are predominantly horst-and-block structures of the central Indian plateau and post-date the Aravalli orogeny. Unlike the Himalaya, which are active, seismically live fold mountains still rising through ongoing Indo-Eurasian convergence, the Aravallis are tectonically quiescent and erosional in character — a classic textbook contrast between young and old fold mountains examined in physical geography.

Recent debate centres on the ecological collapse of the northern Aravallis. Studies cited by the Forest Survey of India and academic researchers indicate the range has been breached at several points around Gurugram and Faridabad, raising fears that the desertification check function is failing; some analyses claim multiple "gaps" of several kilometres have opened through quarrying and urban encroachment. The Centre's proposed Aravalli Green Wall Project, announced in 2023 as part of broader land-restoration commitments, aims to create a 1,400-kilometre buffer of native vegetation flanking the range from Gujarat to Delhi, echoing the Great Green Wall concept of the Sahel. The precise legal status of "Aravalli" land — what constitutes a hill, ridge, or notified zone — remains contested between state revenue records and forest classifications, a definitional ambiguity that has stalled enforcement.

For the working practitioner — whether a UPSC aspirant, environmental policy analyst, or regional administrator — the Aravallis exemplify the intersection of deep geological time, ecological service, and modern governance failure. In examination terms, the range anchors questions on the origin of fold mountains, India's mineral belts, drainage divides, and desertification. In policy terms it is a live case study in the tension between mining revenue, real-estate pressure in the National Capital Region, and the constitutional duty under Article 48A to protect the environment. Mastery of the Aravalli system therefore demands both the physiographic facts and an awareness of the jurisprudence and restoration programmes that now define its fate.