Foregoing of salary:

Once salary accrues, the subsequent waiver by the employee does not absolve him from liability to income-tax. Such waiver is only an application and hence,
chargeable to tax.
Example: Mr. A, an employee instructs his employer that he is not interested in receiving the salary for April 2015 and the same might be donated to a charitable institution. In this case, Mr. A cannot claim that he cannot be charged in respect of the salary for April 2015. It is only due to his instruction that the donation was made to a charitable institution by his employer. It is only an application of income. Hence, the salary for the month of April 2015 will be taxable in the hands of Mr. A. He is however, entitled to claim a deduction under section 80G for the amount donated to the institution.