Guanzhong. Guanzhong refers to the Weihe River basin in Shaanxi, where industry and agriculture are developed and the population is concentrated. The smog in Guanzhong and North China is more serious. Haze is a combination of fog and haze. Smog is very common in cities. In many areas of China, fog and haze are combined as disastrous weather phenomena for early warning and forecasting, which are collectively called "haze weather".