A damaged portion of the Gangotri highway following flash floods and landslides triggered by a cloudburst, in Uttarkashi, Uttarakhand, August 14, 2025.
| Photo Credit: PTI
The Union government is “cognisant” of concerns after sections of highways were washed away following cloudbursts and floods in parts of Himachal Pradesh and Uttarakhand and will frame new guidelines to focus on “slope stabilisation” to curb road collapse during natural disasters, says a senior official of the Road Transport and Highways Ministry.
“We will be issuing new guidelines mandating slope stabilisation prior to road construction, rather than as a post-construction measure, in hilly regions. Additionally, we will revise concessionaire agreements to incorporate these requirements for all future projects,” V. Umashankar, Secretary, Road Transport and Highways Ministry, told The Hindu.
The official said that following the recent incidents of roads collapses, including the 15 damaged sites along National Highway-21 (Kiratpur-Manali Highway), it was observed that the locations that underwent slope stabilisation measures withstood the impact of cloudbursts and floods.
Slope stabilisation is an engineering process of strengthening an unstable slope to prevent landslides and erosion. It involves techniques that increase a slope’s safety by controlling soil or rock movement, managing water drainage, and reinforcing the ground. Common methods building retaining walls, soil nails, anchors, shotcrete, drainage systems, vegetation planting, and adjusting slope shape to improve stability.
Cloudbursts and heavy rain in July and August in parts of Himachal Pradesh triggered road collapses and landslides, blocking National Highway-21 for several days and cutting off connectivity. The highway is a crucial link between Punjab and Leh. The National Highways Authority of India (NHAI) said that 10 sections had been completely washed away and five were partially damaged by floods. The NHAI earmarked ₹100 crores for short-term rectification and said it would examine various options for permanent restoration of the highway.
In Uttarkashi district of neighbouring Uttarakhand, floods in early August damaged National Highway-34, which runs along the Ganga through Uttarkashi district, impacting the pilgrim route to Gangotri.
The official noted that damage to National Highways was predominantly observed in sections constructed along riverbanks, exacerbated by rising river levels due to various factors, including increasing habitation.
The damage was observed on the “valley side”, or the side of the road that slopes down towards the river flowing through the valley below, he added.
Similar events were also witnessed in Sikkim in 2023 after a Glacial Lake Outburst Flood (GLOF). The flash flood, which surged downstream and destroyed the Teesta III Dam at Chungthang, caused water levels in the Teesta river to rise, washing away roads, bridges, and infrastructure, including parts of National Highway-10 which were heavily damaged.
An NHAI official, speaking on the condition of anonymity, said that since 2024, 89 sites on the Kiratpur-Manali Highway had been identified for slope stabilisation treatment. The procedure had been completed at 45% of the locations, the official said, adding that at nearly 40 of the 89 locations, it was being carried out after the construction of the road.
Published – September 23, 2025 10:05 pm IST
