Travel through a village in Africa, and likely as not you’ll see multicolored trash bags twisting through the scrub, like birds signaling for mates. Plastic bags have taken over the continent, caught in thorn trees, blocking sewers, clogging streams. Not in Rwanda. The government passed a law in 2004 banning plastic bags throughout the country. It’s not just enforced in markets: after you pass through customs and immigration at the international airport, you’ll meet an agent, ready to inspect your luggage once more, confiscating all illegal bags. Thousands of Rwandans helped clear the country’s roads and streams when it went plastic-free; the country is now among the continent’s cleanest. Neighboring Uganda soon followed, encouraging the replacement of polystyrene with traditional banana leaves. Kenya, Tanzania, Bangladesh, and Bhutan have since followed with India and Mozambique considering tough new laws.