as in other countries china uses a grading system for monitoring and reporting the quality of freshwater across the country with grade i water the highest quality and grade vplus the worst water meeting at least grade ii is deemed useable for drinking and water quality grade iv or worse inappropriate for contact with human skin the situation remains especially serious for major rivers in the north of the country which pass through large cities including the huaihe and liaohe where well over half of monitored sections were deemed to be grade iv or worse table recent data confirm that other parts of the freshwater system also suffer from serious pollution with of lakes deemed to have water quality grade iv or worse and over half of all lakes and reservoirs assessed as suffering from eutrophication