Income tax relief for arrears, gratuity and commuted pension follows prescribed averaging and filing requirements. Relief under section 157(1) applies where salary, family pension, gratuity, termination compensation, or commuted pension received in a tax year raises the rate of tax. The rule sets out separate methods for computing relief for arrears or advance salary and family pension, gratuity based on length of past service, compensation on termination after continuous service, and commutation of pension, generally by comparing the current year tax with average rates for prior years. For other receipts, the Board may allow relief as it deems fit.