The Ministry of Environment issued the year’s first ultrafine dust advisory for the capital region and South Chungcheong Province as fine dust in the regions rose to alarmingly high levels.

Such an advisory is issued when the daily average density of ultrafine dust particles is expected to stay above 75 micrograms per cubic meter.

With the advisory, the ministry will enforce a set of emergency fine dust reduction measures in Seoul, Gyeonggi Province and South Chungcheong Province from 6 a.m. to 9 p.m. Sunday.

Under the measures, four coal plants in the regions will be halted until 9 p.m., while 31 others will have to run at reduced capacity.

Businesses and facilities that emit air pollutants have to adjust operations, while construction sites are required to reduce or adjust their operations and take steps to curb dust emissions.

The ministry has urged people in the regions to remain indoors, calling for extra caution for the elderly, children and people with respiratory or cardiovascular conditions.