Urban Metro projects in Mumbai have noticed massive growth in recent years and Mumbai Metro Line-3 is one such project planned fully underground from Colaba to Seepz and in construction stage since 2016. Tunnel construction in the financial capital of India has its own unique set of challenges including presence of shallow groundwater table, sound bedrock, presence of heritage, severe, dilapidated buildings, and densely populated slums with heavy traffic movements on roads. Tunnelling in urban environment is always seen as a challenging task on soft ground but even hard ground doesn’t make it easier as blasting in hard basaltic terrain of deccan traps in Mumbai below densely populated slums is extremely challenging. The study includes case of Mumbai Metro Line-3 project, Cuffe Parade section, where the alignment of twin stabling D-shaped tunnels of length 200 m each, 7.6 m height, 7.2 m wide with shallow cover of 15 m and presence of severe to moderate category slums all along the tunnel alignment are proposed to be excavated using controlled blasting technique with robust instrumentation and monitoring scheme. Case study includes optimization of blasting, construction sequence, and challenges faced during excavation owing to deep weathering of basaltic terrain in proximity to sea with vertical weathered joints leading to water ingress. Optimization done during early stages of excavation helped in the successful completion of both tunnels and ground vibrations recorded were well within the permissible peak particle velocity limits of 5–12 mm/sec.