DA is Dearness Allowance, usually given so that employees can cope with rising inflation.
While pursuing my MBA, my professor mentioned that, on average, DA is calculated as around 20% of Basic. However, the actual calculation of DA is much more complicated.
Every year (or semi-annually—I am unsure of the time frame), the government indicates the inflation rate, based on which DA is calculated.
The calculation is a little tricky, and since it wasn't taught to us but rather shared by chance, I happened to forget the formula mentioned in that lecture.
I believe the calculations can be obtained from some government institute, as they are the ones who follow to explicitly include DA in their salary component.
Regarding private firms, as I mentioned, the calculations change periodically, adding to the complexity.
When I asked a similar question to my academic experts, they mentioned:
"Most private firms do not include DA explicitly to avoid the hassle of periodic calculations. The Basic they mention is considered as Basic + DA. So, if inspectors inquire, they would explain that due to inflation, DA increased, but Basic decreased relatively, keeping Basic + DA unchanged."
I am uncertain about the validity of this explanation, but this was the answer shared during our Compensation class.
Senior advice is much needed.