Hyogo Prefecture, which is suffering from poor catches of some fish, has decided to allow greater quantities of nitrogen and phosphorus in wastewater discharged into the Seto Inland Sea, after deeming its water too clean for fish to live in, officials said Monday.
The prefecture plans to set what it sees as Japan's first lower limit on substances affecting the marine environment, possibly within the year. The nonbinding standard includes keeping the minimum nitrogen amount at 0.2 milligrams per liter.
The prefecture also plans to ask local municipalities and companies to cooperate with its plan to introduce the new standards on domestic and industrial wastewater discharges, thought by some to be displacing water that contains the chemicals naturally with unnaturally clean releases.