Environmental pollution costs Vietnam up to five percent of the national GDP annually, according to recent assessments made by the World Bank (WB). It translated into 3.9 billion USD in 2007, and 4.2 billion USD in 2008, said the bank, adding that the country also has to spend another 780 million USD each year on public health treatment due to environmental pollution. According to a survey conducted by the Vietnam Environment Administration, health care costs related to air pollution amounted to 295,000 VND (14 USD) per capita annually in the two northern provinces of Phu Tho and Nam Dinh. Meanwhile, 80 percent of the country's dysentery and diarrhoea cases are caused by contaminated water sources. About six million cases of water-related dysentery and diarrhea have been reported just over the past four years, which incurred total treatment expenses of about 400 billion VND, not to mention indirect costs. Pollution also affects agricultural and aquaculture production, the bank said, citing several cases when industrial factories released untreated waste water into rivers. Environmental pollution, especially air pollution, poses bad impacts on Vietnam’s tourism, while increasing its expense on improving the environment, said the WB.