Held that payments made by assessee to doctors qualified as commission paid for promoting sale of medicines, in view of CBDT Circular No. 5 of 2012, dated 1-8-2012 read with Explanation 1 to section 37(1), payments were not allowable under section 37(1). Principle of tax neutrality would not apply in cases payments have been held to be illegal or are prohibited by law.  (AY. 2013-14)