Which Article of the Constitution of India contains provisions for a National Commission for the Scheduled Castes and Scheduled Tribes?

Article 338 originally provided for an integrated National Commission for Scheduled Castes and Scheduled Tribes. This unified commission was later bifurcated into two distinct bodies via the 89th Constitutional Amendment Act: the National Commission for Scheduled Castes (Article 338) and the National Commission for Scheduled Tribes (Article 338A).