KPMg india offer letter takes how much time ?

Hi I have given HR interview in KPMG on 2 September since then there is no offer letter released as of now although HR is in touch with me and I m asking her she is telling one approval is pending I m getting impatient now although I have one offer from another organization but I want to join KPMG india I have already filled CAF . Can any one tell me how much time it will take my LWD is coming closer as well ??