law: The Income-Tax Act, 1961
  Chapter II
  Basis of Charge
  4. Charge of income-tax.-
  (1) Where any Central Act enacts that income-tax shall be charged for any assessment year at any rate or rates, income-tax at that rate or those rates shall be charged for that year in accordance with, and 3[subject to the provisions (including provisions for the levy of additional income-tax) of, this Act] in respect of the total income of the previous year 4***of every person:
  Provided that where by virtue of any provision of this Act income-tax is to be charged in respect of the income of a period other than the previous year, income-tax shall be charged accordingly.
  (2) In respect of income chargeable under sub-section (1), income-tax shall be deducted at the source or paid in advance, where it is so deductible or payable under any provision of this Act.
  3. Subs. by Act 4 of 1988, s. 5, for "subject to the provisions of this Act" (w.e.f. 1-4-1989).
  4. The words "or previous years, as the case may be" omitted by s. 5, ibid. (w.e.f. 1-4-1989).