Dec 8 (Reuters) - Wall Street’s main indexes opened lower on Tuesday as surging coronavirus cases threatened to hamper an economic revival, while investors awaited progress in ongoing negotiations for a fresh COVID-19 U.S. relief package. The Dow Jones Industrial Average fell 71.84 points, or 0.24%, at the open to 29,997.95. The S&P 500 opened lower by 8.91 points, or 0.24%, at 3,683.05, while the Nasdaq Composite dropped 16.77 points, or 0.13%, to 12,503.17 at the opening bell. (Reporting by Shreyashi Sanyal in Bengaluru)