Definition: In this task, a passage will be given and the goal is to identify an event from the passage. An event is defined as a single word representing something that happened, is happening, or may happen. An event can be factual or hypothetical, positive or negative, certain or uncertain. While most events are based on verbs, an event can also be based on a noun (ex. storm, snow, rainfall) or a copula verb (is, was, been, etc.). The event must not be a pronoun or an adjective. For noun events with multiple words, use the last word in the phrase as event.
Input: Passage: Tehran's Air Quality Control Unit said the Pollutant Standard Index (PSI) -- a standard measurement incorporating carbon monoxide, dust and other pollutants -- has hovered around the "very unhealthy" level of 160 for several days. Such alerts are becoming increasing common, with increased traffic causing the sprawling city's air to be deemed unhealthy for at least 100 days of the year.

causing