Describe the various causes and the effects of landslides. Mention the important components of the National Landslide Risk…

(a) Causes: A landslide is the downslope movement of rock, soil and debris under gravity when slope stability falls. About 12.6% of India's land area (excluding snow-covered areas) is landslide-prone, mainly in the Himalaya, Western Ghats and Northeast. Natural causes include weak rock strata, fault zones, steep slopes, heavy rainfall, snowmelt and earthquakes. Anthropogenic causes include deforestation, unplanned construction, mining, road cutting, blasting and dams, which raise pore pressure, undercut slopes and remove root reinforcement.

(b) Effects: Immediate effects include loss of life and property, damage to roads, railways and dams, river damming and flash floods, as in the 2021 Chamoli rock-ice avalanche and the July 2024 Wayanad debris flows. Long-term effects include degraded farmland, displacement and rehabilitation costs, and damage to forests, soils and biodiversity.

(c) National Landslide Risk Management Strategy (NDMA, 2019): Its components are landslide hazard mapping and zonation (with the Geological Survey of India), monitoring and early warning, awareness and capacity building, policy and regulation on land use and construction, stabilisation and mitigation measures including bio-engineering, and special focus on the Himalaya and Western Ghats, aligned with the Sendai Framework.