WASHINGTON—U.S. business activity slowed moderately in November amid labor shortages and raw material delays, contributing to prices continuing to soar halfway through the fourth quarter. Data firm IHS Markit said on Tuesday its flash U.S. Composite PMI Output Index, which tracks the manufacturing and services sectors, fell to a reading of 56.5 in mid-November from 57.6 in October. A reading above 50 indicates growth in the private sector. The rate of growth remains above the survey’s long-run pre-pandemic average, and is consistent with an economy that is regaining steam after a brief lull in the summer. The services sector accounted for the pull back in activity, with IHS Market noting “some resistance to higher prices.” Though many firms reported business was strong because of increased travel both domestic and international as well as the further easing of COVID-19 restrictions, the pace of growth slowed relative to previous months. “The U.S. …