Explain the geological basis for geothermal hotspots in India. How can direct-use applications benefit Himalayan regions?

Geothermal energy is heat from the Earth's interior. It comes from the radioactive decay of uranium, thorium and potassium and from heat left over from the planet's formation [1]. The Geological Survey of India (GSI) has mapped 381 hot springs in 10 geothermal provinces [1]. India's tectonic setting decides where they occur.

Geological Basis of Hotspots

• Heat reservoir: The semi-solid mantle stores interior heat [1]. Convection currents carry it upward, and it reaches shallow depths where the crust is fractured or tectonically active.
• Himalayan collision belt: The collision of the Indian and Eurasian plates created deep faults and thickened, heated crust. Groundwater circulating along these faults comes up as hot springs at Puga (Ladakh) and Manikaran (Himachal Pradesh).
• Rift and graben zones: Ancient rifts allow deep water circulation. Examples are the Son–Narmada–Tapi lineament (Tattapani, Chhattisgarh), the Cambay graben (Gujarat) and the Godavari valley.
• Coastal faults and island arc: Faults along the west coast and the volcanic Andaman–Nicobar arc form further provinces.
• Reservoir condition: A usable field needs hot water and steam trapped in permeable rock [1]. Where permeability is low, Enhanced Geothermal Systems can engineer a reservoir [1].

Mantle heat → convection → faults/rifts in crust
      → groundwater heated at depth → hot springs / reservoir

Fig: How a geothermal hotspot forms

Direct-Use Benefits for Himalayan Regions

• Space and district heating: Ground Source Heat Pumps and district heating can replace fossil fuel trucked over long routes in cold Ladakh [1].
• Agriculture and food security: Geothermal heat can extend short growing seasons. Puga's early project used it for poultry and mushroom farming [2].
• Livelihoods: Direct uses also include aquaculture and cooling [1]. Hot springs such as Manikaran support pilgrimage and tourism economies.
• Energy security: Heat is available round the clock whatever the weather. Local supply reduces dependence on long supply chains in a strategic border UT [1].
• Environment: Low-carbon heat with reinjection is a sustainable alternative [1]. It protects fragile glacial ecosystems from fuel-burning emissions.
• Policy push: The National Policy on Geothermal Energy, 2025 (MNRE) supports pilots, a national data repository and Centres of Excellence [1].

India's hotspots are the surface expression of collision and rift tectonics, and the Himalaya holds some of the most promising ones. In this region, direct use can bring benefits faster than grid-scale power. Pairing the planned 1 MW Puga demonstration project [1] with clusters of heat pumps and greenhouses can advance SDG 7 and India's Net Zero 2070 goal.