Fine dust levels remain significantly high in most parts of the nation on Sunday.

The National Institute of Environmental Research said that the density of ultrafine dust will hit the "very bad" level for the greater Seoul area and "bad" for western Gangwon, Chungcheong, North Jeolla and North Gyeongsang Provinces on Sunday.

The Environment Ministry issued an ultrafine dust advisory for Seoul, Incheon, Gyeonggi Province, South and North Chungcheong Provinces, enforcing emergency fine dust reduction measures in the regions. It marks the first time the measures were enforced in the second half of this year.

Ultrafine dust particles are smaller than two-point-five micrometers in diameter, commonly known as PM 2.5.

The ultrafine dust is forecast to dissipate from Sunday night as the nation is expected to see rains and strong winds.