Delta Air Lines officially has abandoned the Atlanta-Shanghai route.

According to a May 3 memo filed with the U.S. Department of Transportation, Delta returned to DOT the seven U.S.-China frequencies it had been using to serve the route. Those frequencies, according to a DOT spokesman, will be made available "to another carrier that requests them." The carrier launched nonstop service between the two cities in 2008, but suspended it twice, first in light of "the economic slowdown" and then in January 2012 as a result of high fuel prices and "our overall capacity reduction."