Oil is the biggest revenue earner for the government and it is not easy for Finance Minister P Chidambaram to give up the cash when he is under pressure to finance more populist schemes like NREG and Bharat Nirman but on Wednesday he had no choice. By giving up on customs duties, the North Block will lose about Rs 15,500 crore and reduction of excise will mean another hit of Rs 6,600 crore. Overall the total hit will be in the range of Rs 22,000 crore.