Iraq on Sunday was yet again covered in a thick sheet of orange as it suffered the latest in a series of dust storms that have become increasingly common.Dozens were hospitalised with respiratory problems in the centre and the west of the country.A thick layer of orange dust settled across streets and vehicles, seeping into people's homes in the capital Baghdad.Flights were grounded due to poor visibility at airports serving Baghdad and the Shiite holy city of Najaf, with the phenomenon expected to continue into Monday, according to the weather service.