As per section 74, where it appears to the proper officer that any tax has not been paid or short paid or erroneously refunded or where input tax credit has been wrongly availed or utilised by reason of fraud or any wilful-misstatement or suppression of facts to evade tax, he shall serve show cause notice to the person under sub section(1) at least six months prior to the time limit specified in section 10 for issue of order.