There is no specific limit for cash transactions but as per sec 40A(3) it will get disallowed is payment for a expenditure made to a person in a single day for amount exceeding ₹10000 for mode other than by a/c payee cheque or bank draft or by mode specified under rule 6ABBA. for hire limit is ₹35000. and allowed if exp exceeds limit if condition under rule 6DD satisfied.