No registered non-profit organisation, carrying out advancement of any other object of general public utility, shall carry out any commercial activity unless, —

(a) such commercial activity is undertaken in the course of actual carrying out of advancement of any object of the general public utility;

(b) the aggregate receipts from such commercial activity or activities do not exceed 20% of the total receipts of such registered non-profit organisation of the relevant tax year; and

(c) separate books of account are maintained by such registered non-profit organisation for such activities.