“…First, based on the literature on the economic geography theory, we have included a group of variables intended to show the importance of industry, one of the most polluting sectors, in each region. These variables are, on one hand, the level of industrial production (INDGDP) and the number of industries per square kilometre, or industrial density (DENS), which should favour the level of emissions; and on the other, the interaction of DENS with the weight of industry in regional production (INDW), intended to capture the degree of industrial congestion in the region [32,34]. A negative sign for this interaction could suggest a high concentration, and even congestion, of the industrial sector, which could lead to the displacement of industries to other regions.…”