The Dow Jones Industrial Average was trading near session lows on Tuesday afternoon, a move that puts the blue-chip index in position to eventually mark the first close below its 200-day moving average since July of 2020, according to Dow Jones Market Data. At last check, the Dow /zigman2/quotes/210598065/realtime DJIA -0.56% was down 650 points, or 1.8%, at 34,488, with the 200-day moving average standing at 34,349.12, according to FactSet data. The Dow hasn't closed beneath the measure that market technicians use as a gauge of an asset's long-term trend line since July 13, 2020. The decline, which also was sinking the S&P 500 index /zigman2/quotes/210599714/realtime SPX +0.08% , the Nasdaq Composite Index /zigman2/quotes/210598365/realtime COMP +0.59% and putting the small-capitalization Russell 2000 index /zigman2/quotes/210598147/delayed RUT +0.14% at risk of closing in correction, was sparked by comments from Federal Reserve Chairman Jerome Powell amid the emergence of a new variant of the coronavirus, omicron, that causes COVID-19. Powell told lawmakers it would be appropriate for policy makers to consider speeding up the wind-down of the central bank's monthly asset purchases when the meet next month. Equities were already under renewed pressure after Moderna Inc.'s chief executive officer predicted that current vaccines would be less effective against the new omicron variant of the coronavirus that causes COVID-19.