Landslide Vulnerability in India

Heavy rain caused by the cyclone Remal triggered landslides in several places in Meghalaya, Mizoram, Assam, and Nagaland.

Landslides are a geological phenomenon that involves the sudden and rapid movement of a mass of rock, soil, or debris down a slope under the influence of gravity.
Landslides, usually, occur in areas having characteristics like Steep terrain such as hilly or mountainous areas, the Presence of joints and fissures, or areas where surface runoff is directed or land is heavily saturated with water.

According to the Geological Survey of India (GSI) about 0.42 million square km of India’s landmass, or about 13% of its area, spread over 15 states and four Union Territories, is prone to landslides.
About 0.18 million square km, or 42% of this vulnerable area is in the Northeastern region, where the terrain is mostly hilly.
This area is also prone to earthquakes, which too, are a major trigger for landslides.

Heavy Rainfall: Heavy rainfall is one of the most common triggers of landslides. It increases pore water pressure as well as the weight of soil by making it saturated.
Erosion: Clay and vegetation present within the soil or rock act as cohesive elements and help bind particles together. By removing these cohesive elements, erosion makes an area more prone to landslides.
Earthquakes: Intense ground shaking due to earthquakes causes instability in rocks and soils, thus triggering landslides.
Volcanic Eruptions: Ash and debris deposited by volcanic eruptions overload slopes while the accompanied seismic activity causes instability.

Deforestation: By holding soils as well as obstructing the flow of falling debris, vegetation cover plays an important role in preventing landslides in any area. Deforestation takes away this preventive cover and increases vulnerability to landslides.
Encroachment in Vulnerable Terrains: Of late, humans have been encroaching in landslide-prone areas such as hilly terrains. This has led to increased construction activities in these areas and increased chances of landslides.
Uncontrolled Excavation: Unauthorized or poorly planned excavation activities, such as mining, quarrying, etc destabilize slopes and increase the chances of landslides.
Climate Change: Climate change caused by various anthropogenic activities has led to abrupt alterations in precipitation patterns and increased frequency of extreme weather events.

The Disaster Management Act, of 2005 provides a comprehensive legal and institutional framework for the management of various disasters including landslides.
The National Landslide Risk Management Strategy (2019) covers all aspects of landslide disaster risk reduction and management, such as hazard mapping, monitoring, and early warning systems.
The National Disaster Management Authority (NDMA) has issued Guidelines on Landslide Hazard Management (2009) that outline the steps that should be taken to reduce the risk of landslides.
The National Institute of Disaster Management (NIDM) has been providing capacity building and other support to various national and state-level disaster management authorities.
Early Warning System: Efforts have been made towards better prediction of weather. E.g. Ensemble Prediction System. This will help predict disasters like landslides.

Every mountainous area has a carrying capacity. However development is essential, and one cannot stop the creation of infrastructure. Hence sustainability has to be factored in so that the load does not exceed the carrying capacity.
The National Disaster Management Authority (NDMA) has been working with GSI and other agencies to mitigate and manage the risks from landslides.