Constructing the world’s longest two-way tunnel faced challenges due to harsh weather and tough Himalayan terrain, says BRO chief Lt Gen Raghu Srinivasan. Maintaining extreme caution while digging deep due to cavities surfacing and dealing with the harsh weather and closed roads added to the difficulties. Special fuel had to be requisitioned as diesel froze at -20°C. The project’s altitude at 13,000 ft posed further challenges. This tunnel will improve all-weather connectivity and movement of troops and equipment.