Failure to furnish wealth-tax returns triggers criminal penalties including imprisonment and fines unless specified exemptions apply. Wilful failure to furnish the return of net wealth required under the Act attracts rigorous imprisonment and fine, with harsher terms where the tax that would have been evaded exceeds the higher statutory threshold; lesser mandatory terms apply otherwise. Prosecution is excluded for assessment years before 1 April 1975, and for later years if the return is filed within the assessment year or if tax on regular assessment does not exceed the lower statutory threshold.