A fine dust advisory was issued for Seoul on Monday after the concentration of dust particles in the air rose to alarmingly high levels.

The alert came at one p.m. when fine dust levels hit 157 micrograms per cubic meter. 

A fine dust advisory is issued when the average level of particle matter exceeds 150 micrograms per cubic meter for over two hours.

Gyeonggi Province also issued a fine dust advisory for 19 cities and counties, including Goyang, Gimpo, Dongducheon, Yeoncheon and Paju. 

Authorities have advised children, the elderly and people with respiratory and cardiovascular diseases to stay indoors, while recommending masks for those who go outside.