Tax deduction from salaries: updated computation, reliefs and deductor obligations following recent tax amendments. Circular prescribing deduction of tax at source from salaries under section 192 for 1990-91: tax to be deducted on estimated annual salary at average annual rates, with monthly division and subsection (3) adjustments. It explains Finance Act, 1990 changes (raised exemption limit, revised slabs, introduction/amendment of sections 88, 88A, 80CCB, 80DD, higher 80CCA ceiling and surcharge), defines salary and perquisite valuation rules, enumerates allowed exemptions and deductions (including standard deduction under section 16 and savings rebates), and sets procedural duties of deductors (verification of claims, Form No.16 issuance, TAN quoting, annual returns, correct challan usage and penalties for defaults).