Jakarta faced an air crisis, with 47% of CO2 from congested transport. PT Waskita Karya digitized the 6.4 km  Light Rail Transit (LRT) extension through the dense city using SYNCHRO 4D and iTwin. This digital twin approach, focused on clash detection and 4D planning, delivered measurable climate action during construction, saving 7,356 liters of fuel and reducing construction CO2. The electric LRT is the primary climate solution: it will displace thousands of fossil fuel vehicles, projected to cut 4,000-5,500 tons of CO2 annually. This smart infrastructure is accelerating Jakarta’s transition to zero-emission, clean-air mobility.