Accidentally found out myself (I am just back from a short vacation in Tokyo): one of the guides explained that almost all garbage cans were removed as a conseq

Accidentally found out myself (I am just back from a short vacation in Tokyo): one of the guides explained that almost all garbage cans were removed as a consequence of the Sarin attack in the Tokyo Subway in 1995 - see https://en.wikipedia.org/wiki/Tokyo_subway_sarin_attack https://en.wikipedia.org/wiki/Tokyo_subway_sarin_attack.