Which amendment established the National Commission for Backward Classes? 

The 102nd Amendment of the Indian constitution provided constitutional status to the National Commission for Backward Castes. The One Hundred and Second Amendment Act 2018 of the Constitution of India granted constitutional status to the National Commission for Backward Classes. Article 338B -(1)- There shall be a Commission for the socially and educationally backward classes to be known as the National Commission for Backward Classes. The Commission shall consist of a Chairperson, Vice-Chairperson, and three other Members The conditions of service and tenure of office of the Chairperson, Vice-Chairperson, and other Members so appointed shall be such as the President may by rule determine.