3月9日，在陕西省西安市西华门十字路口，交警戴着口罩执勤。当日，西安遭遇严重沙尘天气，至12时30分空气污染指数已达测试最大值。陕西省气象台发布沙尘黄色预警信号，提示公众尽量减少外出，做好防沙尘的措施。新华社记者 丁海涛 摄     On March 9,,Xi 'an in shaanxi province xihua gate crossroads,The traffic police wore masks on duty.On the day,Xi 'an suffered severe sand and dust weather,To 12 at test air pollution index has reached its maximum value.Shaanxi province meteorological observatory issued sand yellow warning signal,Prompt public out less as far as possible,Make dust prevention measures.The xinhua news agency reporters Ding Haitao perturbation

    3月9日，西安街头沙尘弥漫。新华社记者 李一博 摄     On March 9,,Xi 'an street dust.The xinhua news agency reporters Li Yibo perturbation

    3月9日，在陕西省西安市新城广场，一名儿童在沙尘之中放风筝。新华社记者 丁海涛 摄     On March 9,,Xi 'an in shaanxi province new town plaza,A child in the dust flying a kite.The xinhua news agency reporters Ding Haitao perturbation

    3月9日，两位西安市民用纸巾掩住口鼻抵挡沙尘。新华社记者 李一博 摄     On March 9,,Two xi 'an civil paper towel cover mouth and nose against dust.The xinhua news agency reporters Li Yibo perturbation

    3月9日，西安街头沙尘弥漫。新华社记者 陈钢 摄     On March 9,,Xi 'an street dust.The xinhua news agency reporters Chen Gang perturbation

    3月9日，在陕西省西安市西华门十字路口，一名女交警戴着口罩执勤。新华社记者 丁海涛 摄     On March 9,,Xi 'an in shaanxi province xihua gate crossroads,A ladies wore masks on duty.The xinhua news agency reporters Ding Haitao perturbation