TIANJIN, Oct. 3 (Xinhua) -- North China's Tianjin Municipality issued a yellow alert for air pollution and activated an emergency response on Monday.
According to the city's meteorological bureau, the Air Quality Index (AQI) reading was 173 at noon, with hazardous fine particulate matter PM2.5 being the primary pollutant.
The bureau said rain on Tuesday will help, but the smog will not be dispersed until a cold snap forecast to arrive Wednesday.
Emergency measures were taken following the alert. Factories were partially closed, work on construction sites was suspended, street cleaning was intensified and public transportation was encouraged.
Citizens were also advised to stay indoors and avoid outdoor activities.
Beijing, which is adjacent to Tianjin, also issued a yellow alert for air pollution on Sunday. Heavy smog continued to linger in the city on Monday.
China has a four-tier color-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue.