Eco-Schools runs in tens of thousands of schools worldwide. Its Litter and Waste theme provides PDF lesson plans for ages 6–8, 9–12 and 13–16 in English, Spanish, French and Portuguese, plus home-school versions, all structured around the Seven-Step method (eco-committee, review, action plan, monitoring, curriculum links, informing, eco-code). Not mapped to national codes.
Who made and funded this: the Foundation for Environmental Education (a non-governmental organisation, or NGO) authored the materials; the Litter Less campaign that funded them was sponsored by Mars Wrigley, a confectionery company that is a major user of plastic packaging. We include it because it is NGO-authored and widely used, but tell pupils who paid for it. How to use it: the Seven Steps are a good whole-school structure for our pledge tiers. Free; link only.