The Mumbai Metropolitan Region Development Authority (MMRDA) has granted approval for the selection of Larsen & Toubro (L&T) as the designated contractor responsible for the construction of the city's longest underground tunnel, connecting Orange Gate and Marine Drive.This underground passage is poised to create a congestion-free pathway between Eastern Freeway's Orange Gate and Marine Drive, thereby augmenting connectivity and reducing travel durations significantly.As per the MMRDA's official statement, the Eastern Freeway, which links Mankhurd to Chembur Junction and Orange Gate on P'Dimello Road, has substantially enhanced transportation to South Mumbai. Nevertheless, the escalating traffic congestion around Orange Gate poses challenges for both the Mumbai Port Trust and the Main Post Office square on P'Dimello Marg.To address these pressing concerns and establish a seamless road-based transit network, the MMRDA has outlined plans to construct a 9.23 km corridor, connecting Eastern Freeway's Orange Gate to the coastal road at Marine Drive.The extensive project entails the creation of a 6.51 km twin-tube underground tunnel, with each tunnel accommodating 2+2 traffic lanes, 1+1 emergency lanes, and pedestrian walkways. Additionally, the undertaking includes the construction of a viaduct for vehicle access at the Eastern Freeway Orange Gate, open cuts, and access roads on both sides of the corridor. The left-side tunnel will traverse beneath the seaway and remerge after B. D. SomChowk.Crucially, the project has been meticulously planned to ensure the safety of the underground Mumbai Metro Line-3 project. To achieve this, the tunnel will be situated at a depth of approximately 40 meters from ground level, thereby avoiding any interference with central rail or high-rise building foundations. Given its proximity to heritage sites and densely populated areas in South Mumbai, utmost attention is being devoted to implementing rigorous safety measures throughout the project's execution.Keywords –