Indonesian President Joko Widodo on Monday launched the first elevated rail line for Greater Jakarta, hailing the $2.13 billion project as a step towards easing the capital's chronic road congestion and worsening air pollution.
The driverless, 41.2 km (25.6 miles) Light Rail Transit (LRT) system connects central Jakarta and its satellites cities in West Java, Bekasi and Depok.
People in Greater Jakarta commonly use a 418 km (260 mile) Commuter Line which serve around 1.2 million passengers per day.
Jakarta has been ranked among the world's most polluted cities since May and earlier this month topped the charts compiled by Swiss air quality technology company IQAir.
The president blamed the pollution on excessive road traffic and industries using coal and said nearly 1 million vehicles enter Jakarta each day.
"Jakarta is always on the top 10 of list of cities with the worst traffic jams," he said. "Traffic jams and pollution always exist in Jakarta."
The capital, which has a population of more than 10 million, is also served by an existing, 16 km long underground mass rapid transport (MRT) line that connect the southern areas to downtown Jakarta.
Indonesia has started building a new city on Borneo island called Nusantara to replace the congested Jakarta as capital of Southeast Asia's biggest economy. The project, which has no timeframe for completion, is a key part of the president's legacy as he prepares to leave office next year.