"The government has conducted in-depth studies, and we have intensified the studies in the past three years," the president told reporters. "The result of those studies shows that the most ideal location for the new capital is part of North Penajam Paser Regency and part of Kutai Kartanegara Regency in East Kalimantan."
The project is estimated to cost about US$33 billion ($51 billion). Joko said 19 per cent would be paid for from the state budget, with other funding to come from private investment and public-private partnerships.
The president, who was governor of Jakarta before winning the presidency in 2014, won re election this year in part because of his record of building major infrastructure projects.
He said one reason for picking East Kalimantan is that it does not have a history of natural disasters — unlike islands such as Java, Sulawesi, Bali and Lombok that have been struck by tsunamis, earthquakes and volcanic eruptions over the past 20 months.
He also said that the site is near the country's geographic centre and already has substantial infrastructure.
Building a new capital would require the construction of a new presidential residence, ministry buildings, housing for government workers and highways. Construction could begin as early as 2021.
The target to begin moving to the new capital is 2024, just as Joko's second and final term will be ending.
Jakarta was founded in the fourth century on marshland on the northwest coast of Java and served for centuries as the capital of kings and sultans.
With Dutch colonisation in the early 1600s, it became the capital of the Dutch East Indies and eventually grew into a major port city that was plagued in the early years by malaria.
Today, when combined with the neighbouring cities of Bekasi, Tangerang and Bogor, it forms a vast, teeming megacity of more than 30 million people.
Along the north coast, parts of Jakarta have been sinking more than 2 inches a year, making it one of the world's most vulnerable cities to rising sea levels caused by climate change.
Sea walls have had limited success in holding back the Java Sea, and without an aggressive plan to protect the coast, parts of the city are likely to be lost in coming decades.
In recent years, the city has sought to tackle its traffic congestion by building a subway and an airport rail line. And it has imposed alternate driving days based on odd- and even-numbered license plates in some parts of the city. But for many residents, the efforts are too little, too late.
In July, a group of citizens and activists filed a class-action lawsuit against the president, Jakarta's governor and various government agencies demanding tighter air quality regulations and enforcement to protect the public health. But no quick action on air pollution is expected.
The island of Borneo is split among three countries: Brunei, Malaysia and Indonesia. Proposals to move the capital to Kalimantan, the Indonesian part of Borneo, have been floated for years. Joko recently revived talk of relocation but, until Monday, had been short on specifics.
It is unclear whether the government will pay the enormous cost of protecting Jakarta from rising sea levels at the same time it is building the new capital.
But the president said he was not abandoning Jakarta, which is also the country's financial capital.
"Jakarta will remain as the priority in development and will continue to be developed as a business city, financial city, trade center and service center on a regional and global scale," the president said.
Written by: Richard C. Paddock and Muktita Suhartono
Photographs by: Josh Haner
© 2019 THE NEW YORK TIMES