There is no rule as of date that the Basic should be 50% of the Gross Salary. As per the definition of wages in all labor codes, it will be 50% of Total Remuneration calculated under the definition of wages.
The PF authority has nothing to do with the percentage of Basic with respect to the monthly gross. Moreover, after the verdict of the apex court, PF contribution will also be on other allowances (conditional).
Usually, in most organizations, the percentage of Basic is different in different grades with respect to the monthly gross. This will be common after the implementation of labor codes and as per the definition of wages.
S K Bandyopadhyay (WB, Howrah) CEO-USD HR Solutions [Phone Number Removed For Privacy-Reasons] [Email Removed For Privacy Reasons]
http://www.usdhrs.in
Regards, S K Bandyopadhyay