According to a release, a tunnel ventilation solution developed by Chennai Metro Rail Limited (CMRL) that contributed to cost reductions in the phase-2 project has been honored at the 20th International Symposium on Aerodynamics, Ventilation and Fire in Tunnels (ISAVFT 2024). The award, scheduled to be presented during the symposium in Copenhagen, Denmark, from October 28 to 30, falls under the category of ?sustainability in underground design and construction?. In a paper titled Chennai Metro, India- A case study, authored by Hari Prasad, AGM (mechanical system) at CMRL, and R Singh S Vassoudevane from Systra Infrastructure, the challenges of designing underground stations in densely populated cities were explored. One major challenge highlighted was the limited space available, which necessitates minimizing the footprint of essential service areas such as electrical and mechanical rooms. This optimization is crucial while ensuring functionality, passenger experience, comfort, and safety. The study aimed at optimizing the layout of ventilation systems within Chennai Metro Rail to achieve space and cost savings. One proposed strategy involved placing a tunnel ventilation fan (TVF) at one end of the station and utilizing it selectively when tunnel ventilation and trackway exhaust were unnecessary. This approach reduced the number of fans required from eight to two, resulting in substantial savings in space and costs. Furthermore, the study demonstrated that even with a single TVF, the system meets all fire safety standards. The release attributed the savings realized in the Chennai Metro Rail phase-2 project to the optimization of civil space, reduction in fan numbers, and decreased requirements for connected electrical load and cabling.