Govt declares Joshimath as landslide, susbsidence zone; here's why

Joshimath, Uttarakhand on Sunday was declared as a landslide and subsidence hit zone by the authorities. The development comes almost a week after the cracks started appearing in many roads and houses of Joshimath.

The decision to declare it a landslide and subsidence-hit zone was reached during the high-level meeting which took place among the top officials of the Central government, the state government officials, and officers from agencies like the National Disaster Management Authority (NDMA), Geological Survey of India (GSI) and the National Institute of Hydrology (NIH).

While many refused to vacate their homes and blamed the construction activities for these cracks, according to a report published in The Indian Express, as many as 68 families have been evacuated to relief centres till Sunday. The report also suggests that nearly 90 families will be evacuated soon.

As the Joshimath crisis looks far from being over, here is an explainer on what might have led to the cracks in Joshimath and what is land subsidence.

What is land subsidence?

National Oceanic and Atmospheric Administration (NOAA) defines land subsidence as the sinking of the ground because of underground material movement. 

The sinking can take place owing to a variety of reasons, including, the removal of water, oil, or natural resources, along with mining activities. Earthquakes, soil erosion, and soil compaction.

Reasons behind Joshimath crisis

While the exact cause of land subsidence in Joshimath is uncertain, experts have suggested that it might have occurred because of unplanned construction activities, overpopulation in the region, and obstruction of the natural flow of water and hydel power activities. Joshimath is also a seismic zone, which makes it prone to frequent earthquakes.

According to media reports, the 50-year-old MC Mishra committee report first highlighted the possibility of such an incident occurring. The MC Mishra committee report stated that Joshimath was situated on an old landslide zone, and it does not have high-load bearing capacity. This makes the city extremely vulnerable to ever-burgeoning infrastructure and population.

Moreover, a lack of a proper drainage system might have also contributed to the sinking of Joshimath. According to the experts, unplanned and unauthorised construction led to the blocking of the natural flow of water, which eventually results in frequent landslides.

Many residents have also blamed state-owned NTPC's Tapovan Vishnugad Hydro Power Project for the incident and have alleged that the tunnel had water seepage from a punctured aquifer, leading to the drying of water sources in Joshimath. 

NTPC, however, denied the allegations and in a statement, said, the tunnel built by NTPC does not pass under Joshimath town. This tunnel is dug by a tunnel boring machine (TBM) and no blasting is being carried out presently