Failure to obtain tax audit triggers penalty under section 271B, subject to the reasonable cause exception. Failure to obtain the audit or to furnish the audit report required by section 44AB permits the Assessing Officer under section 271B to impose a penalty for each year of default equal to the lower of a turnover linked percentage of sales/receipts (or gross receipts in profession) or a specified monetary cap, provided no reasonable cause for the failure is proved.