Q. Explain Zero based budgeting?

Zero based budgeting (ZBB) is a method of budgeting, which requires each cost element within the budget to be specifically justified as though it was being under taken for the very first time, without approval, the budget allowance would be zero.  Therefore each cost, every period, must be 'justified' before it can be included in the budget, and employees are encouraged to find alternative ways of accomplishing the same thing but for less money.