There will also be a need for proper drainage facilities, complete with waste water management and, for the chemical wash, waste retrieval using a clarifier or separator.

Agriculture, buildings, energy supply, fisheries, forestry, industry, tourism, transport, waste management and water are sectors that could do with more greening, the report said.

In Japan in particular, the water supply and waste management system were kept far apart, and the Japanese rarely had epidemics of typhoid or cholera.