Under the old tax regime, employees can claim deductions like HRA, Section 80C (up to ₹1.5L), 80D (health insurance), LTA, and standard deduction, reducing their taxable income. The new tax regime (default from FY 2024-25) offers lower slab rates but disallows most deductions and exemptions (except standard deduction of ₹75,000). Employees should choose the regime that results in lower total tax based on their investment profile.