The EC has questioned Portugal on several occasions concerning its alleged failure to use appropriate procedures for energy, transport and tourism related projects. To avoid discrepancies between the conditions set out in an EIA and project implementation, a requirement for a further assessment of projects after their implementation was recently introduced. Emissions of sulphur oxides (SOx) decreased substantially, by 64% between 2000 and 2008, well above the average reduction in the OECD as a whole (-28.1%) (Table 1.1). Reductions in the energy sector and in combustion in manufacturing industry (-74% and -58%, respectively) were especially significant, as they account for a large share of total SOx emissions (Table 3.1).15 The decrease in emissions of nitrogen oxides (NOj was smaller (-13%), but an increasing trend observed in the 1990s was reversed.