Provided by Dow Jones By Caitlin Ostroff and Caitlin McCabe The Dow Jones Industrial Average tumbled Tuesday as concerns about elevated Covid-19 infection levels and a new strain of the virus in Europe overshadowed Congress' approval of a Covid-19 relief package. The index of blue-chip stocks fell 200.94 points, or 0.7%, to 30015.51, marking its largest one-day point and percentage decline in December. The S&P 500 slid 7.66 points, or 0.2%, to 3687.26 to extend its losing streak to a third session. The tech-heavy Nasdaq Composite, in contrast, rose 65.40 p...