Two policemen stand guard to notice pedestrians wearing face masks during the COVID-19 epidemic in Berlin, capital of Germany, Oct. 24, 2020. (Xinhua/Shan Yuqi)

Two tourists wearing face masks rest by a table outside a cafe during the COVID-19 epidemic in Berlin, capital of Germany, Oct. 24, 2020. (Xinhua/Shan Yuqi)

People wearing facial masks are seen on a street during the COVID-19 epidemic in Frankfurt, Germany, on Oct. 24, 2020. (Xinhua/Lu Yang)

Two pedestrians wearing face masks are seen during the COVID-19 epidemic in Berlin, capital of Germany, Oct. 24, 2020. (Xinhua/Shan Yuqi)

People wearing facial masks are seen on a street during the COVID-19 epidemic in Frankfurt, Germany, on Oct. 24, 2020. (Xinhua/Lu Yang)

Pedestrians wearing face masks cross a street during the COVID-19 epidemic in Berlin, capital of Germany, Oct. 24, 2020. (Xinhua/Shan Yuqi)

People wearing facial masks are seen on a street during the COVID-19 epidemic in Frankfurt, Germany, on Oct. 24, 2020. (Xinhua/Lu Yang)