Seoul and Gyeonggi Province ordered preemptive measures on Tuesday to reduce fine dust as pollution levels were predicted to rise to alarming levels in the next few days. 

The measures, implemented on Wednesday, forbid public-sector vehicles with odd-numbered license plates from operating between 6 a.m. and 9 p.m. in the Seoul metropolitan area. 

Pollutant-emitting workplaces operated by public organizations and about 460 construction sites were also required to reduce their operations. 

It is the first time the precautionary measures were enforced since the government announced steps to drastically reduce fine dust in November. 

The measures are enforced when fine dust levels are expected to be bad the day after next in two or more cities or provinces in the capital region or when the daily average level of ultrafine particles are forecast to exceed 50 micrograms per cubic meter for two days.