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Hanoi, the capital of Vietnam, is located in the Northern part of the country in the Red river delta. The urban districts cover an area of 304 km² with an estimated population of 3,147,000 inhabitants. Half of the districts have population densities above 20,000 inhabitants per km² while the other half below 10,000 inhabitants per km². This illustrates the variation between dense urban districts in the centre of the city and districts where peri-urban characteristics prevail. The majority of households have septic tanks that are connected to the drainage network. For Hanoi it is estimated that 82% of the excreta is not managed safely, thus only 18% of the excreta is considered safely managed.