Sikkim: The 20th Mile stretch of National Highway 10, a crucial lifeline connecting Sikkim with West Bengal, has partially reopened after remaining closed for more than a month following a massive landslide. Traffic is being allowed through the affected section in intervals as restoration work continues, while loose soil and unstable terrain remain a concern.
The highway was closed on the night of July 7 after the first landslide struck the area. While workers were clearing the initial debris, a second and much larger landslide developed, extending across nearly 250 metres and worsening the damage.
Roads and Bridges Minister N.B. Dahal, who visited the site, said the area had experienced landslides 15–20 years ago when the road was maintained by the Border Roads Organisation (BRO), but the situation had not been as serious in recent years.
“This year we have faced a major landslide. Earlier, around 15–20 years ago, landslides used to occur at this location as well. Until last year, the problem was not so serious. There used to be small landslides from time to time, but this year the situation has developed considerably,” Dahal said.
He said the month-long closure had severely disrupted one of Sikkim’s principal road links, with vehicles forced to use longer alternative routes. Heavy vehicles have faced particular difficulties because the alternative road is narrow and unsuitable for regular heavy traffic.
The Sikkim Government has been working with the National Highways and Infrastructure Development Corporation Limited (NHIDCL), which is responsible for maintaining and clearing the highway, to restore connectivity.
“Together with our team, we have been clearing the debris for several weeks. From today, we have started allowing traffic, and as you can see, a considerable portion of the road has been opened,” Dahal said.
However, the reopening is being carried out cautiously. Restoration teams are continuing to strengthen the road surface, with traffic being stopped for several hours to allow construction machinery and workers to operate safely.
“Our teams have been working for nearly 24 hours a day. We are trying to clear the remaining debris and make the road safe for traffic. However, because the soil is still loose, we are strengthening and preparing the road surface,” Dahal said.
Traffic may be halted for two to four hours at a time, depending on the progress of the work. Granular Sub-Base (GSB) material is being placed on the affected section to strengthen the road, after which loaded vehicles are expected to be allowed through.
Dahal said the reduction in rainfall had provided some hope that the road could remain open, but stressed that restoration and strengthening work would continue.
The government is also pursuing a permanent solution for the vulnerable stretch. A Detailed Project Report (DPR) for a tunnel has already been prepared, a detailed survey has been conducted and an expert team has been engaged to determine the long-term engineering solution.
“The DPR has already been prepared, and recently a detailed survey of this location was also conducted. An expert team has been engaged to find a permanent solution so that the public does not have to face such problems again next year,” Dahal said.
Technical documents are expected to be submitted around August 20 to the High Court of Sikkim, who are closely monitoring the regular disruption of NH 10 in Sikkim.
Dahal said the Ministry of Road Transport and Highways and NHIDCL are closely monitoring the situation and have assured the state that the highway will be restored.
Dahal also said the new project from Rangpo towards the border is in its final stage and is expected to be completed within the next two years. A river embankment protection project is also underway below the affected section.
The minister said the scale of the current landslide had been considerably greater than previous incidents and could not have been predicted.
“Nobody could have predicted that such a massive landslide would occur. We are confident that a permanent solution will be implemented next year,” he said.
Contractor Dilip Raj Pradhan said the second landslide occurred while workers were clearing the first.
“The first landslide occurred on the night of 7 July. While we were clearing that first landslide, another massive landslide, extending approximately 250 metres, started occurring here,” Pradhan said.
According to Pradhan, eight excavators, including JCB machines, along with two bulldozers have been deployed to clear the debris. He said majority of the road had been cleared for public traffic.
Permanent restoration work, he said, would begin after the monsoon and would extend towards both the affected and upper portions of the stretch.
The exact reason for the repeated movement of the land, however, remains under investigation. Concerns have been raised about the possible role of Teesta River erosion and rainfall, but Pradhan said it was too early to draw a conclusion.
“We cannot say for certain at this stage whether it is happening because of the river below or because of the rainfall,” he said.
A technical investigation, including an SRT test, has been conducted and the final report is awaited. “Once the report comes, we will know the actual reason behind the repeated landslides,” Pradhan said.
Pradhan further said NHIDCL officials had informed him about a proposal to construct a 250-metre-long tunnel through the vulnerable section after the monsoon. He clarified that the proposal had not yet been officially confirmed.
The phased reopening has provided some relief to commuters, although traffic movement remains unpredictable.
Gangtok resident Neeta Sharma said she had waited at the site after receiving information that the highway would open at intervals. She said the alternative route would add significant travel time, particularly while travelling with her child.
Taxi driver Saran Rai said the prolonged closure had affected taxi operators and the public, with commuters frequently relying on social media for updates on whether the highway was open.
“Sometimes it is open and sometimes it is closed. We get information through social media and then come this way,” Rai said.
The 20th Mile stretch also has strategic importance as NH10 provides access towards Nathula and the Sikkim-China border. Dahal said considerable Army movement takes place in the area and that the Army has been assisting restoration operations.