Anzob Tunnel Road. It is also a transit route between Dushanbe and Uzbekistan's capital Tashkent. Prior to construction of the tunnel, especially during winter, the threat of year-round avalanches led to periodic disruptions of commerce. The tunnel was officially opened in March 2006; it was built by the Iranian Sabir Co. Due to the significance of the tunnel, limited traffic flow was permitted via signing a waiver form noting potential hazards such as flooding and smog from construction equipment operating inside the tunnel prior to the final construction phase which may have included installation of ventilation and drainage infrastructure. As of May
Channel Tunnel techniques from the oil industry were employed. Tunnelling was a major engineering challenge, with the only precedent being the undersea Seikan Tunnel in Japan, which opened in 1988. A serious risk with underwater tunnels is major water inflow due to the pressure from the sea above, under weak ground conditions. The tunnel also had the challenge of time: being privately funded, early financial return was paramount. The objective was to construct two rail tunnels, apart, in length; a service tunnel between the two main ones; pairs of cross-passages linking the rail tunnels to the service one at spacing; piston relief