Dear Achinth,
As per 6 (a) unless the articles provide for the retirement of all directors at every annual general meeting, not less than two-thirds of the total number of directors of a public company shall be persons whose period of offfice is liable to determination by retirement of directors by rotatiion.
as per 6(b), at every subsequent AGM, one-third of such of the directors for the time being as are liable to retire by rotation or if their number is neither three nor a multiple of three, then, the number nearest to one-third shall retire fro office.
Total number of directors shall not include independent directors.
illustration: if the Company have 9 Directors consisting of 3 Independent Director, Pursuant to clause 6(a) , 4 directors are liable to determination by retirement by rotation (Independent directors not included) and pursuant to clause 6(b), out of four, one third is liable to retire in AGM, it means one directors is liable to retire.