Fine dust particles filled the skies in Seoul and surrounding areas on Tuesday, prompting authorities to implement emergency dust-reduction measures for the Seoul metro area for the first time this spring. 

According to the Korea Meteorological Administration, the country’s central region is set to see fine dust concentrations reach “bad” levels throughout the day Tuesday.

For fine particulate matter, a concentration of 36 to 75 micrograms per cubic meter is considered bad.

Emergency reduction measures for high concentrations of fine dust will be in place through 9 p.m. Tuesday in Seoul, Incheon and Gyeonggi Province. 

Under the measures, vehicles owned by public institutes will operate on alternate days, while businesses and facilities that emit air pollutants must adjust their operations.

Construction sites will be required to scale down their operations and take steps to curb emissions.

The Seoul metro area is also forecast to see heavy concentrations of fine dust on Wednesday.