China's longest river, the Yangtze, is less polluted than feared, with the amount of metals present less than were in the Rhine River 30 years ago, DPA quoted scientists from a Swiss aquatic institute as saying on Friday. However, in contrast to most rivers in Europe, the number of pollutants found in the Yangtze are increasing. "The increasing industrialization, the rising standard of living, artificial irrigation and generation of electricity is generally increase the pressure on the Yangtze," found Eawag, the Swiss Federal Institute of Aquatic Science and Technology. Water samples were taken in 2006 during an expedition searching for the Yangtze River dolphin or baiji. The Swiss researchers are the first scientists from a foreign country allowed to examine the water quality of the longest river in Asia. Though the dolphin is considered "functionally extinct," chemicals and other pollutants in the river are not solely responsible, reported Eawag. Loss of habitat, overfishing and freight traffic all contributed, though the degradation of the water quality was a factor. The contamination of the Yangtze is comparable to other large rivers where there are occasionally concentrated increases in pollutants that are diluted downstream, concluded the Swiss aquatic institute. However, Eawag warned that the pollutants are putting "devastating pressure" to the ecological system of the Yangtze delta, threatening drinking and groundwater.