Fig. 1: Changes in human behaviour due to the COVID-19 pandemic.

Horizontal variation in population densities (pop km−2) for 15:00 Japan Standard Time (JST) a 18 April to 14 May 2019, b 2020, and c the 2020/2019 change ratio. Traffic counts for d 18 April to 14 May 2019, e 2020, and f the 2020/2019 change ratio and site locations of analysed point: To (Tokyo), Yo (Yokohama), Ch (Chiba), Om (Omiya), Mi (Mito), Ta (Takasaki), and Ut (Utsunomiya) on the Kanto Plain including the Tokyo Metropolitan Area (TMA).