Pupils have to search for information about plastics (properties, production, kinds, recycling, …) in a collaborative way and expose their conclusions. They have to look for different recycling processes in every country. And they have to use the smartphone app Litterati to take pictures of litter and geolocalise it. Besides, they should participate in some local or global Litterati challenge. After studying the results, they have to design a dissemination campaign or to make a proposal to their local authorities.