In monsoon, massive landslides occur in the hilly regions leading to blockage of roads. A landslide is the gravitational movement of a mass of rock, earth or debris down a slope. It occurs when a hilly slope becomes unstable.

The natural reasons of a landslide are groundwater pressure acting to destabilize the slope, volcanic eruptions, earthquakes, erosion, etc. This is one of the natural environmental problems which is influenced by human activities such as deforestation, dynamite blasting of rocks, earth work, constructions, vibrations, etc. These activities need cutting down of trees whose roots hold the soil in place.

In majority of the cases, landslides are triggered by heavy or prolonged rainfall. Landslides are a major hazard in most mountains and hilly regions as well as in steep river banks and coastlines. Landslides cause damage to lives, property and disruption in movement of traffic on highways (linking people living in hilly areas). They are a common feature in hilly areas.