N.Y.C. Admin. Code § 4-206: § 4-206 Displaying a POW/MIA flag over public property.

Until such time as all persons listed as missing in action from any branch of the United States Armed Forces, and all persons from any branch of our armed forces who are prisoners of war, are accounted for by the United States government, the commissioner of citywide administrative services shall assure that the Prisoner of War/Missing in Action (POW/MIA) flag is flown:

(1) over all borough halls every day the American flag is flown; and

(2) over all public property supervised by the commissioner on the dates when the American flag is flown in observance of Memorial Day, Veterans Day, and POW/MIA day.