BEIJING - In Beijing, a weakening cold front means that the acrid smog is likely to continue to haunt the capital.

Beijing's meteorological authorities on Saturday warned of "middle-level pollution" on Sunday, and said that air quality will improve on Monday. However, the city's air could become foul again in the two days following Monday, according to the Beijing Municipal Environmental Protection Bureau.

By 4 p.m. Saturday, hazardous fine particulate matter PM2.5 in some Beijing areas exceeded 220 micrograms per cubic meter.

Most areas in northern China saw another day of choking smog and poor visibility on Saturday as the country renewed the orange alert for air pollution that has lasted for days.

China has a four-tier color-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue.

Poor visibility has caused widespread flight delays and cancellations at Beijing Capital International Airport.

After experiencing frequent bouts of smog, the Chinese public have become increasingly sensitive to the health hazard. To address public concerns, the government aims to cut the density of inhalable particulate matter by at least 10 percent in major cities by 2017.