On Monday, people in the entire metropolitan area, the Chungnam region, and parts of Gangwon-do Province will have to endure high levels of fine dust.
It'll mark the first time fine dust levels are categorized as 'bad' this autumn season.
Experts say it's due to foreign pollutants blowing in from China and other countries, that cannot escape the atmosphere.
"We expect high concentrations of fine dust in the metropolitan area through Wednesday. After that, it's expected to return to normal or good levels."
And with that, for the first time this autumn, the affected regions will carry out new trial measures to reduce fine dust levels.
The preliminary measures first come into effect for the public sector, a day before possible emergency fine dust reduction measures are imposed.
From 6AM to 9PM on Monday, the 'alternate no driving day' system will be in place for all public sector employees in the metropolitan area.
Vehicles working on the African Swine Fever prevention measures in the northern part of Gyeonggi-do Province will be exempt.
Also, working hours of administrative agencies and public institutions will be shortened, and construction sites will be required to take strict measures to prevent further dust being created.
However, in the case of the preliminary reduction measure, there are no emission level 5 vehicle restrictions, and no shortened work days for the private sector.
Lee Seung-jae, Arirang News.