Rapid Building Boom Puts Hundreds of Thousands in Himalayan Disaster Zones

At least 300,000 people in parts of the Himalayas now live in areas that could be hit by natural disasters, a new study shows. Researchers measured the amount of built‑up land in high‑risk zones in northern Nepal, southeastern Tibet and a corner of India’s Uttarakhand. Between 2016 and 2023 the area covered by buildings grew by about 45 %. In places that are especially vulnerable to flooding from glacial lakes, the growth was even faster, rising by almost 78 % over the same period. The study, published in Scientific Reports, was carried out before the August floods that killed more than 1,400 people and left thousands missing.

The researchers, nine in total from the UK, Nepal and India, examined areas up to 50 km (30 miles) downstream from Himalayan rivers and around 1,360 glacial lakes. They found significant development, including tourism facilities, infrastructure projects and real‑estate construction. Pokhara, a major tourism hub at the foot of the Himalayas, has expanded dramatically over the past three decades to accommodate a growing number of visitors.

Mayor Dhana Raj Acharya says the Seti Gandaki River, which flows through the city, poses a huge risk. Many old buildings sit only 5 m (16 ft) from the riverbank, even though new rules require them to be further away. "Where we move them, and how we do that, is the real challenge," he says.

To the north lies the world‑famous Annapurna trekking region, where settlements along riverbanks have increased sharply. Some of these communities have already suffered from recent floods and landslides. Phurpa Chhiring Lama, who runs a homestay there, feels helpless. "Normally all of my 20 rooms are occupied at this time of year – the peak trekking season – but now only five are," he says. "We have been doing this business for more than 40 years, but we’ve never seen this kind of disaster."

Krishna Gauchan, whose hotel is close to the glacier‑fed Modi River, is also worried. "This river can flood if the glacier collapses or if the glacial lake bursts out and we are living in constant fear," he says.

Tourism investors often promote these spots as destinations without fully accounting for the risks, says Khagendra Poudel, a geographer at Tribhuvan University. The situation is similar to parts of north India’s Himalayan valleys that host major pilgrimages.

The president of the Hotel Association Pokhara admits that tourism businesses have expanded "without any proper planning" and have been promoted "haphazardly." "By the time disasters hit, it is too late," says Laxman Subedi. "As a professional body we are trying to create awareness among tourism entrepreneurs and investors."

But tourism is not the only sector. The regions around the Bhotekoshi and Trishuli rivers have seen a significant rise in the construction of hydropower plants. "As river valleys become increasingly populated, development decisions being made today will shape disaster risk for decades to come," warns the study’s lead author, University of Leeds glaciologist C Scott Watson.

The study identified buildings at risk as those within 50 vertical metres (164 ft) of a river or glacial lake’s surface. However, during the catastrophic flooding on 26 August, locals in Rasuwa district say the river level rose by 70 m (230 ft) at some points, so even buildings that were relatively far from the riverbanks were hit and buried by debris‑sludge.

The risks in these areas are largely driven by warming in the Himalayan region, which scientists say is happening at twice the global rate. This rapid warming accelerates the melting of glaciers, icefields, snowpacks and permafrost. The resulting instability can trigger landslides, especially when combined with earthquakes, and can cause glacial lakes to burst, sending deadly floods downstream. Nepal alone has recorded around 30 such events since 1940.

Another problem is that rising temperatures cause rain to reach high altitudes where it used to snow, leading to slope failures, rock and ice falls, and other hazards.

In a recent speech at the United Nations General Assembly, Nepal’s Prime Minister Balendra Shah warned that the country is paying a "colossal price" for a crisis it did not create. "Every major disaster threatens to erase years of development. And it forces a poor country to borrow money to repair damage it did not cause," he said.

Alton Byers, a mountain geographer at the University of Colorado who was not involved in the study, says the findings should serve as a "springboard" to develop more effective early‑warning systems and other precautionary measures. But achieving that will be difficult. Campaigners say building regulations are not enforced on the ground, and development has been haphazard in too many places.

Roads, hydropower projects, hotels and market towns have expanded on the low, flat land along rivers, which is accessible and buildable, says Prof Surya Raj Acharya, an urban‑planning expert and registrar at the University of Nepal. "Those responsible have often ignored safeguards, including keeping off the river bank," he adds. "A fragile ecosystem like the Himalaya demands stricter planning and building regulations than elsewhere, yet these rules have been weak and poorly enforced."

Authorities in Nepal say they are working to address these issues. The national disaster agency will soon ban settlements within 15 m (49 ft) of the riverbank along the recently devastated Rasuwa‑Bhotekoshi corridor. Similar rules are being introduced in other river corridors.

"It is a challenging job because people in many places have sentimental attachments with their land and property but we cannot ignore the increasing risks," says chief executive Dharam Raj Uprety.

A similar story has unfolded across Nepal’s western border in India’s Uttarakhand state, where maximum tourism limits and environmental regulations have been bypassed in the name of economic growth, claims activist Anoop Nautiyal. On paper there are zoning rules that prohibit the construction of houses and infrastructure too close to riverbanks, "but on the ground we see no implementation of such rules. You can see rampant construction all over."

The Uttarakhand government approved new floodplain zoning rules on 12 October to regulate land use and development. "Its objective is to protect life, property and important infrastructure from possible flood damage while maintaining the natural flow of flood waters," the state’s cabinet decision read.

But Basanta Raj Adhikari, director of the Centre for Disaster Studies at Tribhuvan University, thinks it will not be possible to mitigate such threats completely. Insurance grades, he suggests, could be another way to encourage people to build in less risky areas. If authorities were to map places as high, moderate and low risk, he believes insurance coverage would "follow accordingly," ensuring people who build homes in safer areas get better protection.

For now, the pace of construction across the region shows no signs of slowing.

The study’s authors urge governments to strengthen enforcement of building codes, improve land‑use planning and invest in early‑warning systems. They also call for better coordination between tourism, hydropower and local communities to reduce exposure to hazards.

The challenges are not only technical. Many residents have deep emotional ties to their land, and relocating or demolishing buildings can be politically sensitive. Yet the cost of inaction is high: repeated disasters erase years of development and force countries to borrow money to rebuild.

The Himalayan region faces a unique combination of rapid climate change, fragile geology and growing human settlement. The new study highlights how unchecked development can amplify disaster risk. It also shows that even modest increases in built‑up land—just a few percent—can place hundreds of thousands of people in danger.

To protect lives and livelihoods, authorities must enforce existing regulations, adopt stricter zoning, and promote resilient construction practices. Only by combining science, policy and community engagement can the region hope to reduce its vulnerability to the next flood, landslide or glacial lake outburst.