Kenyans collect used plastic bags from Nairobi River to resell in marketplaces near the Mukuru slum in Nairobi. Anyone selling, producing, or even carrying a plastic bag there now risks a €35,000 euro fine or up to four years in prison. Photograph: Wendy Stone/Corbis/Getty

Tourists are being warned to avoid bringing plastic bags to Tanzania from June 1st, when a ban will go into force throughout the country. The Tanzani(...)