Income tax rates and surcharge: thresholds trigger increased surcharge and cess, with special aggregation rules for agricultural income. Income-tax for the assessment year beginning 1 April 2017 is charged at rates in the First Schedule and increased by a prescribed surcharge; where special rate chapters or sections apply, tax or advance tax is to be determined under those provisions with surcharge applied. Net agricultural income above the small exemption is included only for rate determination by aggregating incomes and computing tax on the aggregate less tax on adjusted agricultural income, with higher basic-exemption substitutes for senior residents. Tax, withholding, collection and advance tax attract differentiated surcharge rates by class of taxpayer and are further increased by specified education cesses, with defined terms for application.