West Java, Indonesia - Indonesian President Joko Widodo earlier this year started an ambitious programme of cleaning up an almost 300km stretch of Citarum River, labelled as one of the most polluted rivers in the world.

Pollution comes from many sources: from everyday garbage and domestic waste to thousands of factories dumping their poorly managed waste into the river.

Up to 500,000 cubic metre of rubbish ends up in Citarum river annually, and heavy metal contamination in the water coming from the factory waste has reached critical level.

About 27 million people rely on the river - the longest in West Java province - for irrigation, drinking water and other daily needs, with nearly 80 percent of the capital Jakarta's supposedly 'clean water' sourced from the river.

This is not the first time the government has come up with clean-up programme.

Millions of dollars have been poured into the project before, but with the lack of coordination, maintenance and enforcement, the problem has persisted.

The government, however, is hopeful that this time will be different.