The objective of this paper is to analyze the efficiency and equity consequences of the implementation of an environmental tax. Do the two purposes collide or can they be simultaneously achieved? Using results of the related literature, we show that precise conditions have to be met in order to achieve three goals: increase of the environmental quality, increase of the economic efficiency and improvement of the intergenerational equity. Are such theoretical conditions likely to occur? What are the rooms of manoeuvre for an environmental tax reform in the European countries? In each of them, the revenues of the existing environmental taxes are low in comparison to the weight of the labor taxes (which are highly distortionary). Using European data, we show that, among all the European countries, Belgium, France and, surprisingly, Sweden, exhibit the less green tax system and offer the easiest opportunity to use the environmental tax as a mean to alleviate the tax burden on labor.