via Steve John Powell & Angeles Marin Cabello/BBC Travel

Most first-time visitors to Japan are struck by how clean the country is. Then they notice the absence of litter bins. And street sweepers. So they’re left with the question: how does Japan stay so clean?

On why cleaning the school is part of the curriculum.

Including this element of social consciousness in the school curriculum helps the children develop an awareness of, and pride in, their surroundings. Who wants to dirty or deface a school that they have to clean up themselves?

On how then Japanese became so clean-conscious.

In part, this preoccupation is born of practical concerns. In a hot, humid environment like Japan’s, food goes off quickly. Bacteria flourish. Bug life abounds. So good hygiene means good health.
...in the Zen version of Buddhism, which came to Japan from China in the 12th and 13th Centuries, daily tasks like cleaning and cooking are considered spiritual exercises, no different from meditating.
So why aren’t all Buddhist nations as zealously clean as Japan? Well, long before the arrival of Buddhism, Japan already had its own indigenous religion: Shinto (meaning ‘The Way of The Gods’), said to enshrine the very soul of the Japanese identity. And cleanliness lies at the heart of Shinto. In the West, we are taught that cleanliness is next to godliness. In Shinto, cleanliness is godliness. So Buddhism’s emphasis on cleanliness merely reinforced what the Japanese already practiced.