Environmental activist Deni Riswandani holds up cups of water from the Citarum river (R) and water from a tributary which runs through an area densely populated with textile factories (L) where the two meet near Majalaya, south-east of Bandung, West Java province, Indonesia, January 26, 2018. REUTERS/Darren Whiteside  SEARCH "WHITESIDE CITARUM" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.     TPX IMAGES OF THE DAY
Environmental activist Deni Riswandani holds up cups of water from the Citarum river, right, and from a tributary which runs through an area densely populated with textile factories, left, where the tShow more

Indonesia takes on task of cleaning up 'world's dirtiest river'