A powerful sandstorm blowing over the Gulf has disrupted air traffic in Yemen, and closed schools and sent hundreds of people to hospital with respiratory problems in Saudi Arabia. The Saudi ministry of education announced on Monday the closure of schools in the north, east and south-west of the desert kingdom, a day after similar measures were taken in the capital Riyadh, the official SPA news agency reported. In Riyadh, hundreds of people, mostly children with Asthma and allergies, were treated for breathing difficulties triggered by the storm, according to official statistics released late on Saturday. The storm also affected other Gulf countries, including the United Arab Emirates and Kuwait, where national weather centres warned drivers to use extra caution due to poor visibility and strong winds. In Yemen, the sand storm severely disrupted air traffic in and out of Sanaa’s international airport. At least two flights into the Yemeni capital were cancelled on Monday morning while several others were either delayed or re-routed to the southern port city of Aden, the official SABA news agency reported. Damascus rocked by fighting, Annan team arrives