The East African nation joins more than 40 other countries that have banned, partly banned or taxed single use plastic bags, including China, France, Rwanda, and Italy.
Many bags drift into the ocean, strangling turtles, suffocating seabirds and filling the stomachs of dolphins and whales with waste until they die of starvation.
"If we continue like this, by 2050, we will have more plastic in the ocean than fish," said Habib El-Habr, an expert on marine litter working with the UN Environment Program in Kenya.
Plastic bags, which El-Habr says take between 500 to 1,000 years to break down, also enter the human food chain through fish and other animals. In Nairobi's slaughterhouses, some cows destined for human consumption had 20 bags removed from their stomachs.
A customer packs his foodstuff in a cloth carrier bag in Nairobi, Kenya, Monday, Aug. 28, 2017. A ban on plastic bags came into force Monday in Kenya. Source: AAP
Kenya's law allows police to go after anyone even carrying a plastic bag. But Judy Wakhungu, Kenya's environment minister, said enforcement would initially be directed at manufacturers and suppliers.
Samuel Matonda, spokesman for the Kenya Association of Manufacturers, said it would cost 60,000 jobs and force 176 manufacturers to close. Kenya is a major exporter of plastic bags to the region.
Big Kenyan supermarket chains like France's Carrefour and Nakumatt have already started offering customers cloth bags as alternatives.
