The District’s 5-cent bag tax generated about $150,000 during the month of January to help clean up the Anacostia River, even though residents have dramatically scaled back their use of disposable bags, according a report city officials issued Monday.

In its first assessment of how the new law is working, the D.C. Office of Tax and Revenue estimates that city food and grocery establishments issued about 3.3 million bags in January, which suggests a remarkable decrease. Prior to the bag tax taking effect Jan 1, the Office of the Chief Financial Officer had estimated that about 22.5 million bags were being issued per month in 2009.