China is witnessing the most serious red tide since the beginning of this year, said China's State Environmental Protection Administration (SEPA) in Beijing on May 14.

According to Pan Yue, SEPA's deputy director, the red tide is occurring along the central and southern coast of China's eastern Zhejiang Province, affecting an area of between 8,000 and 10,000 square kilometers.

A report from SEPA's surveillance station in Zhoushan, a coastal city of Zhejiang, said that the tide, started in May 2, still shows no sign of diminishing, probably because "the weather is suitable for the algal bloom to grow."

Red tide is a high-than-normal concentration of the microscopicalgae Karenia. This organism produces a toxin that affects the central nervous system of fish so that they are paralyzed and cannot breathe.

The tide should be blamed, as Pan said, primarily to the industrial and agricultural pollution discharged into Yangtze River. Statistics show that pollution with land source have accounted for over 70 percent of coastal pollution.

"We are going to set up a quick coastal pollution information disclosure system and tighten total emission control of coastal cities,. However, the final pollution lies in the reduction of industrial and agricultural pollution in the upstream of Yangtze River," Pan said.