This discussion clarifies that filing a return for Professional Tax Enrollment Certificate (PTEC) isn't always mandatory. While registration is required for professional tax, the necessity of filing a return depends on individual circumstances. Professional tax itself falls under Section 16(i) of salary-related provisions.
If you are registering for professional tax then you have to register for professional tax enrollment and a certificate regarding that will be issued. Professional tax comes under section 16(i) under salaries