price plummet in indexes and individual stocks

The price plummet in indexes and individual stocks have reflected the impact of the COVID-19 to the world. Analysts and investors began to have a sense of where actual business results could be headed in the next few quarters. The impacts go well beyond just airlines, cruise companies, and companies with big exposure to China. Google, Amazon, Walmart, and even Microsoft all face price pressure because their revenues have big exposure to the above industries and either their suppliers or customers are directly affected by COVID-19.

Please give an example of affected companies and elaborate a bit on how it gets affected.

Just FYI, here is an interactive map (Links to an external site.) that tracks reported cases of COVID-19.

Such only walmart, people need to buy food.