Tackling the Dead Zone isn’t an easy task. About 40% of the continental United States drains into the Mississippi River, and regretfully with all that water comes a lot of nitrogen and phosphorus pollution. This is the pollution that causes the Gulf Dead Zone. With such a large drainage area it is a constant struggle to prioritize where pollution reduction efforts need to happen. However, one area is pretty obvious. The United States Geological Service (USGS) determined that Chicago is the largest contributor of phosphorus pollution to the Gulf.While the Chicago Metropolitan Water Reclamation District (MWRD) did actually add limits on phosphorus pollution in their 2013 discharge permit, the science showed that the limits were not strong enough. So, Natural Resource Defense Council, Sierra Club, Prairie Rivers Network, Friends of the Chicago River and GRN were forced to legally challenge the permit.Two years and several hearings later, the Illinois Appellate Court ruled in our favor, instructing the Illinois Pollution Control Board to re-examine their support of the permit. Yes!This is one small step in the fight to stop the Dead Zone and other impacts of nitrogen and phosphorus pollution.We still need to see numeric limits of this pollution in all of the Mississippi River states, strong regulations and incentives to reduce farm runoff, and real leadership from EPA and the states.Thanks to all who worked so hard to hold the largest single source of phosphorus pollution on the Mississippi accountable.For a more detailed analysis of this decision, see NRDC’s blog.Click here for the Court’s decision.Matt is GRN’s Senior Policy Director