Hi Pavithra,
A CTC means Employee Cost to Co.
CTC = Gross + PF (Employer Contribution) – ESI (Employer Contribution)- Gratuity
Net Salary = Gross – PF (Employee Contribution) – ESI (Employee Contribution) – Professional Tax
PF and ESIC both are employee benefits... you can read about it separately
Your Gross Salary includes Basic + Allowances
Basic is fully taxable, Now if your employer gives you rest of the gross salary as special allowances(Other Allowance), that to becomes taxable.
To help Employees pay less tax Employers distribute the Special Allowance (Other Allowance) in Travel allowance, HRA allowance, Medical Allowance, etc. Some of these allowances require submission of medical bills, rent receipt, etc for your Tax exemption. And some don't require any supporting doc's like Travel Allowance. An Employee doesn't need to pay tax on such allowances. This income becomes totally tax free.
Hope this helps you understand the aforesaid salary components.
In case if you wish to know how you can avail the benefits of the HRA, Conveyance and Medical All. Component, go through the below link
HRA « hrmexpress
Conveyance Allowance « hrmexpress
Section 80D – Deduction in respect of for health insurance premia paid, etc. « hrmexpress