Incoming yellow dust from China is forecast to worsen fine dust levels in the country’s western regions from Thursday afternoon.

The National Institute of Environmental Research predicted that fine dust, or particulate matter smaller than ten micrometers in diameter, to be "very bad" in Incheon and northern Gyeonggi Province on Thursday, above 150 micrograms per cubic meter in density.

Levels in Seoul, southern Gyeonggi, North Jeolla and Chungcheong provinces as well as Gwangju are forecast to be "bad," between 81 and 150 micrograms per cubic meter.

Forecasts say levels will rise further to "very bad" in Seoul as well as the southern Gyeonggi and South Chungcheong provinces.

As of 5 p.m. Wednesday, the "attention" level of the yellow dust alert system was issued for Incheon and Gyeonggi Province.

Meanwhile, occasional precipitation is in the forecast for the southern regions, southern Gangwon and North Chungcheong Province through Thursday afternoon.