Construction activities for the Stations, Systems, Trains, Operations and Maintenance (SSTOM) works of the Sydney Metro – Western Sydney Airport project pose several environmental risks, including noise and vibration, soil and water impacts, air quality degradation, contamination, ecological disturbance, and community impacts. As a Critical State Significant Infrastructure (CSSSI) project, effective environmental management is essential to minimise these risks. This study outlines how the project-specific Construction Environmental Management Plan (CEMP) was developed based on the Environmental Impact Statement (EIS), Conditions of Approval (CoA), ISO 14001 requirements, and relevant New South Wales and Commonwealth environmental legislation. The CEMP is implemented through systematic monitoring (e.g., groundwater, surface water, noise, vibration), compliance tracking and reporting, and regular internal and independent inspections and audits. Continuous review and updating of the CEMP ensure that emerging environmental risks are identified and managed effectively. The results demonstrate that structured planning, rigorous monitoring, and ongoing risk management significantly reduce residual environmental risks during construction. It is recommended that remaining risks be managed through the Operational Environmental Management Plan (OEMP) to ensure continued environmental protection during the operational phase.