Everywhere around the world, a huge amount of plastics is being produced, used and treated every day. A certain amount of these plastics are badly managed and end up in the environment, where they can be problematic. The deplorable state of the ocean as well as other aquatic environments regarding plastic debris has already been mentioned by many studies, but the real origin of this pollution does, until today, remain uncertain. To partially close that gap of knowledge, each step of the lifecycle has been analysed in this project in order to estimate the relative contribution of the losses that can occur at every stage. It came out that around 75% of the plastic losses could be attributed to the packaging and construction domains. To reinforce these estimations, a comparison with the analysed samples from the environment has been done. Although the results need some improvement, the same order of magnitude has been obtained between the estimations and the measurements. However, a less suspected source has shown to be a major contributor to the plastic pollution; the pneumatics from the cars. Even though the pneumatic losses haven’t been integrated in the final relative contribution, due to their absence from samples, their problematic aspect still remains. In fact, this source pollutes the environment a 100 times more than the construction domain for example, which points it out as an important source that needs attention.