Indonesia has a new capital city deep in the lush forests of Borneo. Nusantara will soon replace Jakarta, a city built by the Dutch in the 17th century that has grown into one of the largest metropolises in the world with a population of over 30 million people. The new capital could not be more different: it is planned as a forest city with 75 per cent of the land set aside to provide access for wildlife; buildings will be connected by walkways to encourage pedestrians; and there is a commitment to green energy and transport from the start. Nusantara's architects and planners, all of them Indonesian, have set out a dream of a global city to be built over the next two decades, growing to house a population of four million. President Joko Widodo has even announced plans to bid for the 2036 Olympics there. The ambition is a city that represents the diversity of Indonesia and balances economic development across the archipelago, which for decades has been concentrated on Java. That island is less than a tenth of the area of Indonesia but is home to 60 per cent of the population and the same share of the economy. This has come at a high cost. Jakarta is sinking more rapidly than any other city on the planet and suffers from regular floods. The city was until recently the largest without a metro system; now it has just one line connecting 13 stations. The vast sprawl of concrete and motorways is covered most days in a thick haze; it is regularly ranked as the world's most polluted city. But Indonesia the country is taking a £40-billion gamble on whether moving the capital will help alleviate the problems of Jakarta and provide other benefits such as balancing economic development. The site chosen for Nusantara is near the coast of Borneo, close to the provincial capital of East Kalimantan and in an area with rapid economic growth due to energy and mineral extraction. Purpose-built capitals have a poor record of achieving their ambitions; they often end up as soulless monuments to oppressive regimes. They are also both a symptom and a driver of bad government by leaders who become isolated from their people. Will the remoteness of Nusantara cut Indonesians off from the leaders at a time when their quality of democracy is in decline? As the world's largest Muslim country and the third largest democracy, it is a question that matters beyond its shores.