This directive prohibits employment discrimination on the grounds of religion or belief, disability, age or sexual orientation. Article 2 prohibits both direct and indirect discrimination and defines harassment as amounting to discrimination. Articles 4-6 provide for exceptions to the principle of equal treatment. Other key provisions of the directive include shifting of the burden of proof and the prohibition of victimisation. Article 15 acknowledges the particular situation obtaining in Northern Ireland and provides that steps taken to correct the imbalance in the number of teachers and police personnel from the underrepresented religious group will not constitute discrimination to the extent that it is expressly provided for in the national legislation.