Japan aims to cut social contact by 80%, here's why

TOKYO -- Residents in Tokyo, Osaka and five other prefectures have been asked to refrain from going out. The plea came after the central government on Wednesday decided to become more aggressive in combating the novel coronavirus and declared a state of emergency. Aichi prefecture declared one of its own on Friday.

The request that residents of big metropolitan areas stay home came out of the belief that by reducing social contact by 80% in those areas, these population centers can stymie the virus.