The achievement of positive Environmental Performance (EP) at national level could strongly depend on differences in regional features, namely economic specialization, regulation stringency and innovation capabilities of both public institutions and the private business sector. We apply both shift-share and econometric analysis on a new NAMEA available for the 20 Italian Regions, in order to provide evidence of the role played by sector innovation, technological spillovers and regional policies in shaping the geographical distribution of EP. The Italian North-South divide regarding industrial development and productive specialisation patterns seems to affect regional EP. Nonetheless, such pattern presents some interesting differences, revealing a more heterogeneous distribution of emissions, which may reflect the role of other driving forces. In particular, agglomerative effects seem to prevail over purely internal factors - environmental efficiency of neighbouring regions strongly influence the internal EP. This means that together with the clustering of specific sectors into restricted areas as a standard result in regional economics, there is also some convergence in the adoption of cleaner or dirtier production process techniques. Finally, regional technological spillovers seem to play a more effective role in improving environmental efficiency than "sector internal innovation", revealing that accounting for spatial features is crucial to understand the key drivers of EP.