Dear Satheesh
Sec 192 states tax is to be deducted for payments that would be taxable under the head "salaries"
Sec 17 defines salaries in a inclusive manner. Incentives n bonus, though not specifically covered in definition, are outcomes of employement hence, they r to be taxed under salaries.
Since, they fall under the income salaries "tax is supppsed to be defucted"