Employees provident, pension and deposit linked insurance schemes may be framed, modified, and given retrospective effect for covered workers. Section 15 authorises the Central Government to notify Employees Provident Fund, Employees Pension and Employees Deposit Linked Insurance schemes for specified employees or establishments, to frame other social security schemes for self employed or other classes, to modify such schemes prospectively or retrospectively, and to provide that schemes under clauses (a)-(c) may address matters in Parts A-C of the Fifth Schedule with specified effective dates.