Sensex falls 850 pts, Nifty below 24,900; why are markets down today?

Why are markets falling? Rising Covid-19 cases in Asia, including India, Moody's downgrade of US ratings, and fall in US futures are some of the reasons why markets are down today

Sensex falls 850 pts, Nifty below 24,900; why are markets down today?
Why are markets falling? Rising Covid-19 cases in Asia, including India, Moody's downgrade of US ratings, and fall in US futures are some of the reasons why markets are down today