The water of the Surabaya River in East Java has turned chocolate brown, and with a mercury concentration 100 times over the tolerable limit established by the World Health Organization, has experienced massive fish death and a rise in severe pollution-related illnesses in communities along its banks.

In 2008, an NGO called Ecological Observation and Wetland Conservation (ECOTON) won a case against the governor of East Java to establish limits on pollution discharged into the river and a system to monitor it. ECOTON also launched an education campaign on water pollution, and communities and industries have improved significantly their waste disposal procedures.