S. 12A : Registration-Trust or institution-Retrospective registration-Delay in application-Assessee having claimed exemption under section 10(23C)(iiiad) from inception, being aware of statutory requirements, but not seeking registration under section 12A and failing to furnish cogent and justifiable reasons for delay-Denial of retrospective registration held justified. [S. 10(23C)(iiiad), 260A]