As far as contributions to overall pollution are concerned, this is generally neglected at the level of a particular project. An important milestone is reached when an impact study is performed and a public hearing is held. When these procedures first began, the impact study was only when the project had already reached a fairly advanced stage, with the decision in principle to build it already essentially having been taken, and the transportation route already approximately fixed. The influence of the impact study was thereby reduced, it could result only in slight modifications to the technical characteristics or, at the limit(and then rarely), in postponement of the project. In a different form, the environmental impact assessment could have provided a valuable input to the decision-making process. However, in all countries, the impact study is now being done earlier in the life of the project. In France, for example, a recent circular from the Ministry of supply provides for an impact analysis of projects at the outset of planning new projects, with appropriate consultation of the associations involved.