Waiver of time limit for cancelling protective assessments allows officers to correct redundant assessments on merits. The Board authorises Income-tax Officers to cancel redundant protective assessments-either suo motu or on application-by treating them as mistakes apparent from record or by admitting and disposing of rectification applications, and, where necessary, to waive the statutory time limit for such action; each relaxation of the time limit must be reported to the Inspecting Assistant Commissioner within one month.