Is there any rule as to how long can a company keep an employee on probation?

Is there any rule as to how long can a company keep an employee on probation?

That depends on the nature of job. It can be six months, one year or even two years. But the period of probation should not be to misuse the concept.

Period of probation in a company depends upon company's policy. Some companies allow 3 months probation period while some others have 6 months probation to one year. Company has sole right to extend probation period for another 3 months, 6 months, or for year, if it is found that the job performance of the probationer employee is not upto the desired level.

It is 06 months or 03 Months varies from Company to Company.

Some companies will treat you confirmed employee from the date of joining, but leaving the company with a 30 or 90 days notice period is vice-versa.

The max. duration of probation is provided in the applicable rules, in case of industrial establishments, it is to follow the provision in Certified Standing Orders or else the Model Standing Orders. At the end of probation period the suitability of the employee for being retained in service is to be assessed, in cases of unsatisfactory service, the probation period can be extended, but that cannot be extended indefinitely.
So pl try to see the applicable rules in this regard and if there is still a query, pl come back with full details of the Rules applicable.