The awareness of the climate emergency makes environmental issues a priority at many levels. In addition to political initiatives, research on the reduction of the environmental impact of human activities is on the rise. Among these activities, the transportation sector is among the most polluting. In parallel to the efforts to electrify vehicles, many works are focusing on the reduction of gaseous pollution of thermal engines. On the other hand, a significant amount of research is being done on the automation of vehicle driving. Thus, the suppression of the human factor can allow a reduction of the road accidents, an improvement of the comfort as well as a better energetic efficiency, this last one reducing by the same time the fuel consumption. However, before reaching a fully autonomous vehicle, and considering the great complexity of this task, many intermediate steps must be taken. Thus, connected vehicles, coupled with connected infrastructures, allow the emergence of Collaborative Intelligent Transport Systems (C-ITS). The applications of such approaches allow a large number of applications. Here also, they allow to improve safety while reducing greenhouse gas emissions. In this article, we focus on the reduction of environmental footprints through C-ITS. The review of different contributions from the literature, highlights the possibilities offered by such technologies.