Fraudulent tax evasion triggers notice with interest and escalating penalty options and limited time bars for assessment. Where the proper officer believes tax was unpaid, short paid, erroneously refunded or input tax credit wrongly availed by reason of fraud or wilful misstatement or suppression of facts, he shall serve a show cause notice specifying tax, interest and a penalty equivalent to the tax. The officer may issue supplementary statements for other periods on the same non fraud grounds. Taxpayers may voluntarily pay with a reduced penalty to avert notice, or pay higher reduced penalties within prescribed short periods after notice or order to conclude proceedings; the officer must determine amounts after considering representations within the statutory assessment time bar.