1 . ECSC - PRODUCTION - STEEL PRODUCTION AND DELIVERY QUOTA SYSTEM - FIXING OF QUOTAS - APPLICATION OF THE RULES IN FORCE - UNJUST AND DISCRIMINATORY NATURE - NONE ( ECSC TREATY , ART . 58 , DECISION NO 1831/81 ) 2 . OBJECTION OF ILLEGALITY - MEASURES THE ILLEGALITY OF WHICH MAY BE PLEADED - INDIVIDUAL DECISIONS - EXCLUDED ( ECSC TREATY , ART . 36 ; THIRD PARAGRAPH )