Annual Salary increment - 5% increment to an employee then would it be to the Basic salary or to the gross salary?

I would be grateful if I could get information about how the salary increment is done in India.
Say if you were to give a 5% increment to an employee then would it be to the Basic salary or to the gross salary.
Any information provided would be a big help.

Hi!
Salary increments worldwide are always added to the BASIC (base) PAY. and, the average worldwide salary rate increase is 3% -5% year on year.
But, the four (4) basic compensation principles must always be considered in any decision relative to Salary Increases or adjustments. These are: Internal Equity, External Competitiveness, Affordability, & Sustainability.
Best regards.

Thank you for taking the time to reply.

Hiyoshi san,
You are welcome! Am happy to be of help.
I used to work with Toyota Motor Philippines, Inc. And, i Have been to Japan (Nagoya & Toyota City) before.
Thank you for joining our group.
Best regards.

please tell about understandably these four : Internal Equity, External Competitiveness, Affordability, & Sustainability.

Hiyoshi San,
In India, it is always on gross salary. Most of the companies follow this way.