Initiation of safeguard investigations: applications or suo motu action require evidence of market disruption and causal link. Rule 5 requires the Director General to initiate investigations on a domestic producer's written application supported by evidence of increased imports, market disruption or threat of market disruption, and a causal link between imports and the disruption; the Director General must verify the accuracy and adequacy of that evidence before initiating proceedings and may also initiate investigations suo motu when satisfied that equivalent evidence exists from specified sources.