Landslides in India: Vulnerable Areas and Risk Reduction

Every monsoon, news channels flash images of collapsed highways in Himachal Pradesh, buried homes in Wayanad, or stranded pilgrims in Uttarakhand. Behind these headlines lies a recurring geological hazard that quietly shapes life in hilly regions: the landslide. As per the Geological Survey of India, about 0.42 million square kilometres – roughly 12.6% of the country’s land area – is prone to landslides. Understanding where these events strike, what triggers them, and how communities can reduce risk is no longer a niche concern. It is central to planning safer hills, roads, and settlements.

What exactly is a landslide? 🔗

A landslide is the rapid downslope movement of rock, soil, debris, or vegetation under the pull of gravity. The material can fall, topple, slide, spread, or flow. Sometimes the movement is slow and barely noticeable – a creeping slope that distorts walls over years. At other times, entire hillsides collapse within minutes, wiping out villages before anyone can react. The intensity of a landslide depends on factors like the steepness of the slope, the amount of vegetation cover, the bedding plane of rocks, and tectonic activity in the region.

Landslides rarely occur in isolation. They often accompany earthquakes, cloudbursts, floods, or volcanic activity. In hilly regions, a single trigger can set off a chain of slope failures across a watershed.

The landslide map of the country 🔗

Two regions dominate the national landslide map: the Himalayas and the Western Ghats. According to the National Disaster Management Authority (NDMA), landslides and avalanches affect roughly 15% of the landmass, covering the Himalayas, the North-Eastern hill ranges, the Western Ghats, the Nilgiris, the Eastern Ghats, and the Vindhyans, in that order.

The Himalayan belt 🔗

The Himalayan region – including Jammu & Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and the North-Eastern states – tops the list. The mountains here are geologically young, still rising due to the collision of the Indian and Eurasian plates. The Indian crust moves at about 5 cm per year, creating continuous stress that leaves rocks friable and fracture-prone. Add heavy monsoon rainfall, snowmelt, and frequent seismic activity, and you have a perfect recipe for slope failure. Satellite data from the Indian Space Research Organisation identifies Rudraprayag and Tehri Garhwal in Uttarakhand as the most landslide-prone districts in the country.

The Western Ghats 🔗

The Western Ghats stretch through Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu. Although this belt sits in a relatively stable geological domain, it experiences frequent landslides during the monsoon. Steep slopes, deep soil cover, and intense monsoon rainfall make this region India’s second most landslide-prone area. Nearly 17,000 sq km in Kerala alone, mostly along the western side of the Ghats, is mapped as landslide-prone.

Other hotspots 🔗

Landslides are not limited to these two giants. The Nilgiris in Tamil Nadu, the Araku region of Andhra Pradesh in the Eastern Ghats, the Meghalaya Plateau, and parts of the Konkan coast also see regular incidents. Even the Andaman and Nicobar Islands report occasional slope failures.

Why do hillsides give way? 🔗

Landslides result from a combination of natural and human factors. Rarely does a single cause bring down a slope – it is almost always a cocktail of conditions.

Geological and geomorphological causes 🔗

Steep slopes, weak and fractured rocks, and unstable soil profiles set the stage. In the Himalayas, the young and still-uplifting terrain means rocks are brittle and joints are numerous. The Western Ghats, in contrast, struggle with thick lateritic soils over hard bedrock – a combination that absorbs monsoon water, becomes heavy, and then slips off the rock beneath.

Heavy and intense rainfall 🔗

Rainfall is the most common trigger. Water saturates the soil, raises pore-water pressure, and reduces the friction holding particles together. A study of global rainfall-triggered landslides found that of all such events, about 16% were reported from India, with 77% occurring during the monsoon. Climate change is making this worse. Short, intense cloudbursts – once rare – are now increasingly common, giving slopes little time to drain.

Seismic activity 🔗

Earthquakes shake loose material and trigger massive slope failures. The 1991 Uttarkashi earthquake, the 1999 Chamoli earthquake, and the 2011 Sikkim earthquake each set off large numbers of landslides across their respective regions.

Human factors 🔗

This is where the story gets uncomfortable. Deforestation strips away the root networks that bind soil. Unplanned road cutting for highway expansion creates unstable vertical faces. Quarrying and mining remove the support at the base of slopes. Hydropower tunnels, hotel construction on fragile ridgelines, and unchecked urbanisation in hill towns add loads that the slopes were never designed to carry. A combination of deforestation, mining, and road construction has been repeatedly flagged as a major driver in both the Himalayas and the Ghats.

The human and economic cost 🔗

Landslides are among the deadliest and most expensive hazards in hill regions. They do not just take lives – they sever roads, cut off villages for weeks, and cripple agriculture, tourism, and power supply.

The Wayanad tragedy of 2024 🔗

In the early hours of 30 July 2024, a massive debris flow tore through the villages of Mundakkai and Chooralmala in Kerala’s Wayanad district. The Kerala State Disaster Management Authority later confirmed it as the largest landslide in India’s recorded history, with a debris flow of roughly six million cubic metres – enough to fill 2,400 Olympic-sized swimming pools. The runout stretched eight kilometres from the crown of the slide. Most victims were tea and cardamom estate workers, asleep when the disaster struck. The event was preceded by about 570 mm of rainfall in the two days leading up to the tragedy, a textbook case of how extreme rainfall can overwhelm already-fragile slopes.

Infrastructure and livelihood losses 🔗

A single major landslide can wipe out decades of development. Roads, railways, bridges, and communication lines are often the first to go. Farms and plantations buried under debris take years to recover, if they recover at all. For hill economies that depend on tourism – think Himachal Pradesh or the Nilgiris – even the perception of risk can empty out hotels and guesthouses for an entire season.

Reducing the risk: what actually works 🔗

Unlike earthquakes, landslide risk is substantially manageable. With the right mix of science, engineering, and community action, slopes can be stabilised and lives saved.

Hazard mapping and zonation 🔗

The first step is knowing where the danger lies. The Geological Survey of India, under the National Landslide Susceptibility Mapping Programme, has mapped 4.3 lakh sq km of landslide-prone terrain. The Indian Landslide Susceptibility Map now offers 100-metre spatial resolution and is reported to be over 95% accurate. NDMA guidelines recommend hazard zonation at 1:50,000 scale, with finer scales for critical corridors.

Slope stabilisation and engineering works 🔗

Once a risky slope is identified, engineering interventions step in. Retaining walls, rock anchors, soil nailing, shotcrete, and gabion structures hold loose material in place. Drainage channels carry away the water that would otherwise saturate the soil. In several Himalayan road corridors, these measures have reduced the frequency of closures during the monsoon.

Afforestation and bioengineering 🔗

Tree roots are nature’s rebar. Planting deep-rooted native species on degraded slopes binds soil, intercepts rainfall, and slows surface runoff. Vetiver grass, bamboo, and indigenous broadleaf species are widely used for bioengineering in both Himalayan and Western Ghats regions. Combined with engineering works, this approach is cost-effective and ecologically sound.

Early warning systems 🔗

Perhaps the most transformative development is the rise of modern early warning systems. NDMA has backed a pilot low-cost monitoring system using MEMS-based sensors and artificial intelligence that detects soil movement and issues SMS alerts, sometimes a full day before a major slide. Strain gauges, slope displacement meters, and groundwater sensors feed data in real time, allowing authorities to close roads or evacuate villages before disaster hits.

Policy and institutional support 🔗

The National Landslide Risk Management Strategy (2019), released by NDMA, consolidates the national approach. It covers hazard mapping, monitoring, early warning, awareness, capacity building, regulations, and stabilisation. The Landslide Risk Mitigation Scheme (LRMS), launched in 2019, has signed memorandums of understanding with Sikkim, Mizoram, Nagaland, and Uttarakhand to fund site-specific mitigation projects.

Land-use planning and building regulations 🔗

None of the above works without sensible land use. Restricting construction on steep slopes, enforcing setback rules along hill roads, and updating municipal bye-laws in hill towns remain the most cost-effective mitigation tools. Unfortunately, these are also the hardest to implement, as tourism demand and political pressure often override planning norms.

Community preparedness matters 🔗

Even the best sensors cannot replace alert, informed communities. NDMA advises residents of landslide-prone areas to watch for warning signs such as cracks in the ground, the sound of rock fall or cracking trees, and moving debris, and to evacuate to safer areas when heavy rainfall alerts are issued. Keeping a stocked emergency kit, knowing the nearest relief camp, and participating in mock drills transform panic into preparedness.

Schools and colleges in vulnerable districts are gradually introducing disaster management into their curriculum. Training local administrators, panchayat leaders, and volunteers ensures that when sensors raise an alert, there is a ready chain of response on the ground.

Where the country stands today 🔗

Progress is visible but uneven. Hazard maps are better than ever, legislation is in place, and technology-driven early warning is moving from pilot to deployment. Yet landslide fatalities remain stubbornly high, largely because settlement patterns and construction practices in hill regions have not caught up with scientific knowledge. The Wayanad disaster exposed gaps in early warning accuracy, in-disaster coordination, and post-disaster recovery that policymakers are still trying to close.

Climate change complicates the picture further. Warmer atmospheres hold more moisture, translating into heavier rainfall in shorter bursts. What counted as a once-in-a-century event a generation ago may well become a once-in-a-decade event by mid-century. Landslide risk reduction, in other words, is not a one-time engineering problem – it is a long-term commitment to living more carefully with the land.

What do you think? Should hill towns impose stricter limits on construction and tourism to protect fragile slopes, even at the cost of short-term economic growth? And how can early warning alerts be made to reach the most vulnerable residents – often daily-wage workers in remote estates – in time to save lives?

References

1. https://ndma.gov.in/Natural-Hazards/Landslide
2. https://compass.rauias.com/disaster-management/landslides-types-impacts-areas-india-ndma-guidelines/
3. https://www.sciencedirect.com/science/article/pii/S2666592124000040
4. https://blog.lukmaanias.com/2022/10/06/topic-landslides-story-of-fragile-himalayas-and-vulnerable-western-ghats/
5. https://pwonlyias.com/pyq/differentiate-the-causes-of-landslides-in-the-himalayan-region-and-western-ghat-150-words-10-marks/
6. https://www.downtoearth.org.in/natural-disasters/a-month-after-indias-deadliest-landslide-ever-wayanad-villages-begin-to-recover
7. https://vajiramandravi.com/upsc-exam/landslides/
8. https://link.springer.com/chapter/10.1007/978-3-031-89836-5_11
9. https://www.sciencedirect.com/science/article/pii/S2666592125000472