On 9 December 2014 an oil spill occurred at the Sela river of Sundarbans, Bangladesh, a UNESCO World Heritage site, when an oil-tanker named Southern Star VII, carrying 350,000 litres of furnace oil was sunk in the river after it had been hit by a cargo vessel. By December 17, the oil spread over 350 km2 area. The slick spread to a second river and a network of canals in the Sundarbans and blackened the shoreline. The event was very threatening to trees, plankton, vast populations of small fishes and dolphins. The event occurred at a protected Sundarbans mangrove area, home to rare Irrawaddy and Ganges dolphins.