According to prediction models by the National Observatory of Athenss Meteo weather service, dust clouds started sweeping in from the Sahara, North Africa, on Tuesday and will last through Saturday.
While the phenomenon is not unprecedented for the season, it is unusual to last more than two to three days.
Apart from casting a shadow over many parts of the country and affecting visibility, the thick dust is also a potential public health hazard, especially for people with asthma or other breathing difficulties.