Real decreto 287/2001 de 16 de marzo por el que se reduce el contenido de azufre de determinados combustibles liquidos. BOE n° 75 de 28/03/2001 page 11532

This administrative measure establishes limits for the sulfur content in specific liquid fuels used in Spain. Its primary goal is to reduce air pollution and improve environmental quality by lowering the emission of harmful sulfur oxides. This affects fuel producers, distributors, and importers who must ensure their products meet the specified sulfur concentration levels to remain compliant with national environmental standards.