OSAKA--Littering has long soiled the bustling Dotonbori district here as tourists who enjoyed takoyaki and other local specialties often just tossed away the plastic trays and sticks. But now ...

Dotonbori refers to a canal, a street that runs parallel to it, and the general entertainment district in the heart of Osaka. Its history dates back to 1612 when Yasui Doton (1533-1615 ...