Why Nepal Keeps Building Roads Through the Himalayas — Even When the Mountains Keep Destroying Them

Nepal cannot stop its mountains from moving. But it also cannot stop moving food, fuel, medicine, passengers and trade through them. Across Nepal, critical highways have to survive steep slopes, intense monsoon rainfall, rockfall, landslides, river erosion and some of the most difficult road-building terrain in the world. In this documentary, we follow the engineering behind Nepal’s mountain-road system — from the 2026 failure at Krishnabhir on the Prithvi Highway corridor to the slope-stabilization work used along the Narayanghat–Mugling road. At Krishnabhir, early reporting described around 70 meters of road as completely collapsed and roughly another 120 meters as severely cracked. After an 18-day disruption, a new connection roughly 270 meters long restored two-way traffic. But restoring access did not mean the long-term instability had been permanently solved. That distinction is at the center of this story. The World Bank estimates that the Nagdhunga–Naubise–Mugling corridor carries around 60–70% of the goods entering Kathmandu, including food, fuel, construction materials and medicines. On the 33-kilometer Narayanghat–Mugling section, more than 8,000 vehicles travel each day. Engineers widened the road and treated more than 100 slopes using combinations of drainage and bioengineering, while 23 more complex slopes received stronger site-specific treatments including methods such as wire mesh, anchors, rock bolts, retaining systems and drainage. The lesson is not that one engineering technique can defeat the Himalayas. Different slopes fail for different reasons. Rain can saturate susceptible material. Surface runoff can damage shoulders and drainage systems. Rock can fall from fractured cut faces. High river flow can erode support from below. And road construction itself changes slope geometry and drainage conditions that engineers then have to manage. That is why a mountain road is much more than asphalt. It is a system of slope stabilization, drainage, retai