Jakarta has begun commercial operation of its first metro line, with many hoping it will ease the notorious traffic in Indonesia's capital.
The new line is the first phase of a larger Mass Rapid Transit (MRT) project, covering a 16km route so far.
It follows two weeks of a trial run where people could use the trains for free.
Other public transport initiatives have failed to ease traffic, as most people use private cars, correspondents say.
The new MRT is a significant step for Indonesia's capital where there have been discussions about an underground metro dating back to 1985.
The second phase is expected to be completed in 2024 with additional extensions planned for later.
'Getting people to use the MRT is a real challenge'
By Abraham Utama, BBC Indonesian
Before the launch of the MRT, Jakarta already had public transport systems in operation, such as the TransJakarta bus rapid transit and a commuter train.
But those mass transport systems have failed to become the first choice for Jakarta residents. Only 20% of Jakarta's population use public transportation for their daily commute.
The director of Jakarta's new MRT Jakarta told me that shifting people from private cars to using the MRT will be a real challenge. He's also urged the Jakarta metropolitan government to issue some regulations that will force residents to leave their cars and motorbikes at home.
In other words, Jakarta's metro cannot be the only solution to the heavy traffic problems. Parking tariffs and car sales tax should be increased, and there should be a toll road system, experts have said.
The projects are part of a large push that President Joko Widodo hopes will improve Jakarta's infrastructure, and boost his popularity ahead of national elections on 16 April.
He inaugurated the line on 24 March, six years after construction had begun on the Japanese-funded project.
"This is my very first time to use Jakarta metro service," passenger Budi Sukmono told the BBC. "I took a day off today so I could bring my family to experience this."
"I usually do my daily commute on my motorbike. I think I could spend less money if I use the metro - fuel prices keep increasing these days."
"While the metro is clean and comfortable, I haven't yet decided whether I will use if for my daily commute," passenger Maria Wace told the BBC.