Hi Sweta..
Typically there are three components like Fixed salary, Variable salary & benefits.
Fixed includes Basic, DA, HRA, PF, PT, SA ( This includes earnings as well deductions)
Variable includes Special allowance, Project allowances, Bonus, Performance pay, Incentive, etc
Benefits part includes car plan, Holiday package, Leased accommodation, Telephone, Medical / Hospitalization schemes etc.
These put together forms CTC.....
As for the Taxable and Non Taxable....
Sodexho and some medical allowances are considered to be non taxable... Most of other allowances are either brought under the Income Tax Act or FBT act...
So, it is advisable that you check the FBT act before making any alteration to your current salary structure.