Income-tax rates and surcharge regime, with aggregation rules for agricultural income and separate company insurance treatment. Income-tax is charged at rates in the First Schedule with surcharges as applicable; where an assessee has net agricultural income plus total income above specified thresholds, tax on total income is computed by aggregating total and agricultural income and then subtracting tax on agricultural income increased by a basic amount, with modified surcharge treatment in certain bands. Companies with life-insurance profits pay aggregate tax: that portion at life-insurance rates and the remainder at company rates. Withholding and advance tax computations use rates in Parts II and III respectively. Key terms are defined.