Restriction on follow-up assessments during election period limits notices for preceding years when searches yield no evidence. Restriction on issuance of assessment notices for six preceding years applies where searches or requisitions during an election period seize cash or assets but yield no evidence or investigation for earlier years. The investigating officer, with Director General approval, must certify that the search/requisition occurred in a notified constituency or that seized assets are connected to the election process and that no evidence exists for previous years; the certificate is to be communicated to the Commissioner and Assessing Officer, limiting unnecessary proceedings.