In this paper we propose an analytical approach to obtain so-called efficient policies in terms of environmental and economic objectives. A policy is said to be efficient if any environmental or economic achievement is obtained with the minimum possible detriment to other relevant objectives. We apply this concept obtain the minimum possible environmental impact for a given growth rate or, symmetrically, the maximum economic growth for a given amount of polluting emissions. We present an application to Spanish economy with 2000 data using a Computable General Equilibrium model. We evaluate the efficiency of the observed policy and give some policy recommendations. Finally, we give an idea about how to enlarge the analysis by including additional objectives.