Voluntary disclosure of concealed income can avert Section 273 penalty if advance tax payment and compliance conditions are satisfied. Penalty under Section 273 should be sympathetically and liberally withheld where a taxpayer, prior to detection, voluntarily and in good faith makes full disclosure of concealed income, furnishes any required statement or estimate of advance tax and pays the advance tax by the prescribed deadline so that tax paid meets the stipulated proportion of assessed tax, files the required return in the prescribed manner and time, and cooperates in enquiries; assessing officers are directed not to initiate penalty proceedings in such cases.