BEIJING — China’s weather observatory issued on Oct 5 a yellow alert for smog that is expected to hit the capital of Beijing and neighboring regions in northern parts of the country.

Beijing, Tianjin and parts of Hebei, Liaoning and Shandong provinces will be shrouded by smog from Oct 5 to 6, the National Meteorological Center (NMC) forecast.

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

The NMC warns people in the affected areas to reduce outdoor activities.

The smog coincides with the week-long National Day holiday, and many tourists are vacationing in Beijing.

Beijing authorities also issued a yellow alert for smog on the evening of Oct 5, the first warning of serious air pollution in the fall this year.

A spokesman with Beijing Municipal Environmental Monitoring Center said weak winds and humid air have made pollutants hard to disperse. In addition, satellite monitoring results showed that mass pollution was caused by intense straw burning on the North China Plain.

According to the city’s contingency plan for serious air pollution, under the yellow alert, dust control on construction sites should be enhanced and some operation, such as dismantling of buildings, should stop.

It is predicted that air quality in the Chinese capital would improve from the night of Oct 7.

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.