| Quality Issues | South Asia | South-East Asia | Pacific Islands | P.R. China | Japan, Australia, and New Zealand |
| Pathogenic agents |
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| Organic matter |
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| Salinization |
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| Nitrate |
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| Fluoride |
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| Eutrophication |
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| Heavy metals |
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| Pesticides |
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| Sediment load |
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| Acidification |
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