ANNAPOLIS, MD (AP) – The health of the Chesapeake Bay is getting a better grade in an annual environmental report card. The University of Maryland Center for Environmental Science gave the health of the nation’s largest estuary a C grade for 2020. That’s up from a C-minus in 2019. Individual indicators of bay health had mixed results in 2020, but the report says the overall bay-wide trend continues to improve. The report says seven out of 15 regions showed significantly improving health trends. Dissolved oxygen and total nitrogen scores improved, while chlorophyll and total phosphorus scores declined.