BEIJING - Large parts of China's northern regions will be blanketed by smog over the next three days, the National Meteorological Center (NMC) said on Monday.

The authority continued to issue a yellow smog alert. Yellow is the second lowest level in China's four-tier color-coded weather alert system.

The density of PM 2.5 - airborne particles measuring less than 2.5 microns in diameter, exceeded 150 micrograms per cubic meter early Monday morning in most parts of northern and northeastern China. The density of PM 2.5 surpassed 245.3 micrograms per cubic meter in Tianjin, according to NMC monitoring data.

Smog will cover central and northern China from Monday to Wednesday, the center forecast.

It warned of a decline in air quality and advised residents in these regions to stay indoors or take precautions.

Meanwhile, flurries of snow and sleet will hit Qinghai Province, as well as Tibet and Inner Mongolia autonomous regions, while rainstorms will hit Xinjiang Uygur and Guangxi Zhuang autonomous regions over the next 24 hours, the NMC said.

It also forecast rainfall in the provinces of Hubei, Hunan, Yunnan and Hainan.