(a) any restrictive trade practice-
(i) upon receiving a complaint of facts which constitute such practice 2[ from any trade association or from any consumer or a registered consumers' association, whether such consumer is a member of that consumers association or not or
(ii) upon a reference made to it by the Central Government or a State Government, or
(iii) upon an application made to it by the 1[ Director General], or
(iv) upon its own knowledge or information