Section 7(1)(a) in The Chennai Corporation (Superior) Service Pension Rules, 1970
(a)such department proceedings, if not instituted while the pensioner was in service, whether before his retirement or during his re-employment, shall, after the final retirement of the officer, be deemed to be a proceeding under this rule and shall be concluded by the authority by which it was commenced in the same manner as if the officer had continued in service;