by Paul R. La Monica, CNN Business — July 19, 2021 . Investors are getting spooked by the rising numbers of Covid-19 cases as the Delta variant spreads across the globe. The Dow fell about 725 points Monday, a drop of 2.1%. The S&P 500 ended the day down 1.6% and the Nasdaq was 1.1% lower. This was the worst day for the Dow since a 943-point drop in late October, and it was the biggest decline this year. But the blue chip market barometer has had several even bigger point plunges since the start of 2020 due to concerns about the Covid-19 pandemic. The Dow plummeted more than 1,000 points six times last year, with five of those market meltdowns taking place in March at the start of the pandemic in America. The Dow suffered its biggest point slide ever on March 16, 2020, dropping nearly 3,000 points — a 13% freefall.