There are 21 days because they are the days considered necessary to change a habit. The goal is to publish a video on social media a day with advice, tricks, or ideas to reduce the production of waste in the daily lives of each one. We started with videos on invisible waste (central theme of EWWR2020) to raise awareness of the reduction in the consumption of goods and then, every day, we will publish videos from Cascais Ambiente and from the packaging waste management systems on the themes of reduction, reuse and recycling.