Income tax surcharge structure prescribes layered surcharges and special levies on specified income categories and exports. Income tax and super tax for the assessment year beginning April nineteen sixty-three impose layered levies: income tax and super tax at schedule rates are increased, where applicable, by surcharge, special surcharge and additional surcharge; computation rules allocate tax proportions where specific heads (notably salaries and life insurance business) form part of total income; withholding and advance tax incorporate additional surcharge; and specified export-related deductions and exclusions provide limited relief, subject to caps and Board-prescribed computation rules.