 The Chesapeake Bay has gotten its best environmental grade in more than 20 years. It's only a C+, but the score from the University of Maryland Center for Environmental Science is up from a C. The group says we're starting to see the results of a lot of hard work. It attributes the change to sewage treatment upgrades and measures taken to improve air quality. The report looks at indicators including the condition of aquatic vegetation, total levels of phosphorus and nitrogen, and water clarity.