Dear
Are we talking about the workman category who comes under the purview of th4e industrial disputes act, 1947, if yes, the probation period shall be as per the Model Standing Orders of the State. Even if you are having certified standing orders, the probation period can't be more than the period mentioned in the model standing orders of the state. Normally it is six months which can be extended upto one year maximum.
If does not cover under the ID Act, 1947 than as per service rules of the company/as per terms of letter of appointment.
ak malhotra
Sr General Manager