I’ve been thinking about reports like these for a while, and suppose you had a study that said 100% of all COVID-19 cases in the world are in people who live in

I’ve been thinking about reports like these for a while, and suppose you had a study that said 100% of all COVID-19 cases in the world are in people who live in areas with less than healthy air pollution. Does that mean the air pollution causes the disease? Because nearly everyone in the world lives in such an area.