Urbanisation, Extreme Rainfall, and Disaster Risk in the Himalaya

The Himalaya are experiencing the long-term impacts of colonialism and marginalization from centres of power, capital-based degradation, unplanned urbanization and uncertain climate change in the form of recurring disasters. These events represent the slow violence being experienced by communities across the region. One such event occurred on 4 October 2025. A heavy deluge hit the Darjeeling, Kalimpong and Sikkim Himalaya, as well as Nepal and Bhutan. The region received red and orange alerts for lightning, thunder and rainfall. The notifications on peoples’ phones were followed by incessant rain, loud thunder and bright lightning flashes throughout the night.

It was the third day of Dasai, one of the main festivals of the hills, which falls mainly in the month of October. Dasai, which was previously characterised by clear skies and sunny weather, has become a rainy festival over the past decade.  Many elderly people spoke about never having seen such lightning and thunder before. The rainfall predicted at 2cm, increased to 3cm in some locations. This volume is almost 10 times the critical threshold of 25mm per day for the occurrence of major landslides in the Himalayan Region. The rains, lightning and thunderstorms throughout the night kept people awake, especially the ones closer to the rivers and streams.

Overnight, the Chota Rangit River in Bijanbari, one of the blocks of Darjeeling district, swelled and turned deep brown. It flooded homes and homestays with swimming pools, sweeping some of them away and filling up the swimming pools with silt to the brim. A little ahead, Chota Rangit had swept away a part of the road that connected to a bridge to Pulbazar. However, it was not just the main river that was growing. Streams overflowed, triggering landslides that damaged houses and buildings under construction. People’s newly constructed houses as well as their lands were swept away.

In Bijanbari, the police and fire brigade sprang into action, evacuating the inhabitants of the riverside area. Establishments and houses have been creeping up along the banks of the rivers and into the forested areas in the mountains. Communities that have moved into the regions in recent years are pushed to inhabit unsustainable geographies, such as those with higher and steeper slopes or close to streams and rivers. Additionally, the hill or mountain owners – families that own hills upon hills – are also subdividing the hills into parcels and selling them to newer inhabitants. These newer communities rarely have place-based contextual knowledge. Even with erstwhile expertise and technical know-how, the contractors in the hills have been infamous for building over whatever “vacant” plot they can see, which can be above public toilets, over water bodies, or at hairpin turns of streets. They appear to be underinformed of the dangers of investing in quick returns with no paperwork and tempting the wrath of nature.

Disasters caused by rainfall are becoming increasingly common in this region, even after the monsoon. The timing of the recent disaster coincided with the second anniversary of the 3 October 2023 Chungthang disaster on the River Teesta. This highlights the extension of rains beyond the monsoon months – June, July, August and September indicating change in rainfall patterns and an increase in the volume of rain received on a daily or hourly basis. Major rivers such as the Teesta have been overflowing every year, multiple times a year with the streams and tributaries of the Teesta, such as the Chota and Bada Rangit, creating damage along their routes.

Call to Action

With no awareness in place and back-cutting of the mountain, houses were left unprotected, and landslides became uninvited guests at the recent Dasai celebrations, breaking up some families and even wiping out entire families in some places.

The uncertainty of climate change is becoming increasingly evident by the day, with communities that are recent settlers or those developing homestays for income being the worst affected. This highlights the rapid and unplanned development occurring near water bodies. On the one hand, the communities migrating into these disaster-prone regions are caught unawares needing consistent support with historical knowledge. On the other, it marks the inconsiderate push for developing for profit.

Considering that the Indian Himalaya, along with Nepal and Bhutan faced this deluge with many casualties, this calls for not only a local but a regional and transboundary understanding of the interaction of extreme rainfall events and urbanization, and their impacts across the length of the rivers, beginning from the first-order streams to their sinks in the oceans.