273B. Penalty not to be imposed in certain cases.

Notwithstanding anything contained in the provisions of clause (b) of sub-section (1) ofsection 271, section 271A, section 271AA, section 271B, section 271BA, section 271BB, section 271C, section 271D,section 271E, section 271F, section 271G, clause (c) or clause (d) of sub-section (1) or sub-section (2) of section 272A, sub-section (1) of section 272AA or section 272B or sub-section (1) of section 272BB or sub-section (1) of section 272BBB clause (b) of sub-section (1) or clause (b) or clause (c) of sub-section (2) of section 273, no penalty shall be imposable on the person or the assessee, as the case may be, for any failure referred to in the said provisions if he proves that there was reasonable cause for the said failure.