The death toll in Himachal Pradesh rose to 75 on Friday (August 18) after another body was recovered from the rubble of a Shiv temple in Shimla. Twenty-two of the deaths have occurred in three major landslides in Shimla, including the one at the temple. Six people are still feared buried in the temple debris. Himachal has always been highly vulnerable to landslides during the monsoon. Over the years, the vulnerability of the steeply sloping, geologically young and unstable Himalayan ranges has been greatly exacerbated by human activity such as deforestation, road-building, terracing, and changes in agriculture patterns that require more intense watering. The National Institute of Disaster Management’s (NIDM’s) ‘Landslide Hazard Zonation Atlas of India’ puts most of Himachal Pradesh — an area more than 38,000 sq km — in the “high” hazard zone, which includes areas that are the second most prone to landslides. A smaller area, about 7,800 sq km, lies in the most vulnerable “very high to severe” landslide hazard zone. The NIDM’s ‘Archival Records and Documentation of Socio-Economically Significant Landslides in India’, published in 2022, contains accounts of all major landslides in India going back several decades. Among the significant landslides in Himachal Pradesh are: Shimla, 1971 A massive landslide in Snowdon, Shimla, in 1971 destroyed an under-construction six-storey medical college. At the site of the landslide, a 21.5 m high, 37 degree slope had supported a dispensary and a hospital building at its top for a number of years, without any noticeable signs of stress. Encouraged by the seeming stability of the slope, the six-storey building was built at its toe, with a planned extension between the main building and the upper slope, to be created by cutting into the mountain itself. However, the attempted excavation to build this extension led to minor cracks appearing in the dispensary building, which eventually developed into a well-defined landslide in February 1971. This landslide was one of the first to trigger an alarm over the wanton construction in Shimla. As per assessments made at the time, only two-storey buildings, subject to a geologist’s clearance, were viable on sliding or sinking areas. Construction on the slopes has far surpassed this. “Most of the town is built on slopes between 45 and 75 degrees. Some 90 per cent of central Shimla, built on a 60 degrees slope, is covered with buildings which are four to five stories high,” the NIDM report says. In order to cut costs, “pillars for buildings are embedded in loose soil”, making such construction extra vulnerable to landslides. “The town, which was built for a population of just 25,000 in the early 20th century, today houses close to 3,00,000 people,” the report says. Construction is poorly planned and executed, as a result of which a large number of people are potentially in danger from landslides. Naina Devi, 1978 The Naina Devi range, where the venerated temple and town are located, is a linear hill range on the lower Shivalik mountains. While the area had been stable for long, the town was constructed on an overburden — soil and ancillary material above the bedrock. The region saw unprecedented rainfall in the monsoon of 1978. A crack was observed at the floor of the temple warehouse on August 1. Over the next few days, a number of cracks appeared in the surrounding areas. Nearly 30 cm of land subsidence was observed on August 6. A massive landslide occurred on August 24 due rain causing overburdened material to oversaturate, resulting in increased weight and pore water pressure, and reducing the cohesion and shear strength of the material, says the NIDM report. Over the span of two hours, the slide carried a chunk of the slope, including 143 structures, a portion of the road and some portions of the temple steps, down a distance of 150 m. Luckily, all inhabitants had abandoned their homes and moved to safer places by the time calamity struck. The landslide risks from deforestation were flagged at the time. “Tree roots play an important structural role on hill slopes. The roots, winding through the soil and often penetrating bedrock, add strength to the soil in the same way that steel rods reinforce concrete. When trees are felled, these roots begin to decay; the hill slope gradually loses its resistance to failure, resulting in landslides,” states the NIDM document. Road construction in the hills has been a major factor behind deforestation. The use of explosives in road construction has opened up fissures in the slopes. Kangra, 2021 Kangra, Himachal’s westernmost district, has been frequently impacted by natural disasters. Flash floods are common, and a 1905 earthquake caused widespread devastation. Most of the district is geo-environmentally fragile due to the presence of soft to semi-consolidated tertiary rock in the lower reaches of the mountains, and the presence of closely spaced major Himalayan thrusts in the upper reaches. On July 12, 2021, the village of Boh, roughly 50 km from Dharamshala, was hit by a massive landslide. Boh lay on the foot of the slope, across a riverbed. Amid torrential rain, initially small stones and debris started coming down the slope. Suddenly a massive landslide occurred, destroying seven houses, other constructions, roads and agricultural land. Ten people were killed. The Kangra landslide was notable because of two things. First, due to the rain, first responders and authorities took nearly six hours to arrive at the spot. This brought attention to the importance of training citizens in the basics of responding to such calamities. Second, poor drainage was found to have played a major role in the event. Illegal encroachments and lack of maintenance had created barriers in natural as well as man-made drains in the area, leading to water and debris accumulating. Over time, this added to the pressure on the slope that was already fragile, and eventually led to the landslide. Shimla, 2021 On September 30, an eight-storey building at Shimla’s Kachi Ghati collapsed like a deck of cards within a few seconds, and also turned two more buildings located below it into rubble. Videos of the building collapse went viral on social media. The building's foundation had started to give way a couple of days earlier, and the building had been consequently evacuated. No loss of life was reported due to the incident, but the damage to property was estimated at around Rs 6 crore. After an investigation, authorities made some damning yet not-so-startling revelations. As the name ‘Kachi' (raw/unprepared) suggests, the slope on which the landslide occurred comprises loose strata of debris dumped during construction activity in the main town. The area at the entrance to the town has several high-rise buildings, even though the terrain is not suitable for heavy structures. These structures are also violative of building regulations in some cases. This particular building collapsed, along with a chunk of the hillock, due to seepage which weakened its foundations. “There are widespread violations in most multi-storey buildings… Most buildings, precariously located on steep slopes, have illegally raised additional floors and their owners are using the basements for residential or commercial purposes, which are meant to be non-habitable,” the NIDM document says. The flourishing tourism economy in Shimla has led to many houses being converted into hotels. The NIDM document states that the state’s authorities and the Tourism Ministry have actively encouraged this, turning a blind eye to the potential risks of such unchecked development. Notably, the document says such disasters cannot be ruled out in the future.
