Which Article of the Constitution provides that it shall be the endeavour of every state to provide adequate facility for instruction in the mother tongue at primary stage of education?

Article 350A was inserted by 7^th Constitutional Amendment Act, 1956. It says, it shall be the endeavour of every state and of every local authority within the state to provide adequate facilities for instruction in the mother-tongue at the primary stage of education to children belonging to linguistic minority groups; and the President may issue such directions to any state as he considers necessary or proper for securing the provision of such facilities.