Why in news?
In early October 2025 torrential monsoon rains triggered landslides and flash floods across the eastern Himalayas. Darjeeling district and parts of Sikkim were the worst affected. Roads and bridges were washed away, homes were damaged and several dozen people lost their lives. The disaster forced authorities to evacuate tourists and shut down transportation links.
Understanding landslides
A landslide is the rapid movement of soil, rocks and debris down a slope. Gravity pulls loosened material downward when it becomes unstable. Heavy rain, earthquakes, deforestation and construction can all upset the delicate balance on steep hillsides. In mountain regions the risk is high because slopes are steep and rock strata are young and weak.
Why are the eastern Himalayas vulnerable?
- Unstable geology: The Himalayas are young folded mountains still rising. Rocks and soil layers have not fully settled, making them prone to slipping when saturated with water.
- Intense rainfall: The region receives heavy monsoon showers. Prolonged downpours saturate slopes and reduce friction between soil particles.
- Unsustainable development: Rapid urbanisation, road construction and illegal quarrying disturb hill slopes. Removing vegetation weakens root binding and increases runoff.
- Climate change: Rising temperatures change rainfall patterns. Intense cloudbursts and glacial melt add sudden loads of water, increasing the likelihood of slope failure.
Historical context
The Darjeeling region has recorded many devastating slides in the past. Major incidents occurred in 1899, 1968, 1975 and 2011 when continuous rainfall triggered massive slope failures. Each disaster resulted in heavy casualties and damage to the hill railway and roads. Despite repeated warnings, unsafe construction and deforestation have continued, keeping the area on edge during every monsoon.
Impacts of the October 2025 event
- Loss of life and property: Dozens of residents died when houses collapsed. Several bridges and stretches of the Darjeeling Himalayan railway were damaged.
- Isolation of communities: Landslides cut off mountain villages, hampering relief work. Road closures affected tourism and the tea industry.
- Environmental degradation: Slopes stripped of vegetation saw increased soil erosion, siltation of rivers and destruction of wildlife habitats.
Measures to reduce landslide risks
- Early warning systems: Install rain gauges and sensors on vulnerable slopes to alert authorities before saturation triggers a slide.
- Strict land‑use planning: Prohibit construction in high‑risk zones and enforce building codes suited to hilly terrain. Stabilise cut slopes with retaining walls and proper drainage.
- Eco‑friendly practices: Encourage reforestation, terracing and bio‑engineering (using vegetation to bind soil). Maintaining tree cover helps absorb rainfall and stabilise slopes.
- Community preparedness: Train local residents in evacuation drills, first aid and communication during emergencies. Establish rescue teams and stockpile relief supplies.