Constructing the world’s longest two-way tunnel presented numerous challenges due to the harsh weather conditions and tough Himalayan terrain, according to Lt Gen Raghu Srinivasan, the Border Roads Organisation (BRO) chief. The engineers faced difficulties such as cavities surfacing while digging deep and the need for extreme caution while working. The construction work was also hampered by the harsh weather conditions and the closure of roads for most of the year. Special fuel had to be brought in to prevent diesel from freezing at temperatures as low as -20°C. The altitude of the project site at 13,000 ft further complicated the task of maintaining communication lines and transporting equipment and personnel. The Covid-19 pandemic also impacted the project, delaying the movement of machinery and supplies. However, the completed tunnel will provide all-weather connectivity and improve the movement of troops, materials, weaponry, ammunition, and stores for the Army.