Under Section 20, the Authority's competence to enter into and perform contracts necessary for discharging its functions under the Act is expressly made:

Section 20 grants the Authority general contractual capacity - competence to enter into and perform any contract necessary for discharging its statutory functions - but this general competence is expressly made 'subject to the provisions of section 21', which then lays down the detailed MODE of executing such contracts (who signs, sealing requirements, and the two-tier Authority-level/Central-Government-level approval thresholds for high-value or long-term contracts). Section 20 is thus a source-of-power provision, while Section 21 is a procedural/mode-of-exercise provision; neither is complete without the other, and this deliberate cross-reference (rather than any absolute or CAG-approval-based formulation) is often glossed over by candidates.