China is tightening air quality standards and expanding its "blue sky" days, but South Korea's air quality continues to rank among the world's worst every winter and spring. With foreign inflows and domestic emissions intertwined, attention is focused on whether China's improvements will translate into cleaner skies for Korea.
China Accelerates Push for 'Blue Skies'
According to state-run Xinhua News Agency on Feb. 25, China announced it would apply stricter fine dust standards. The plan calls for tightening annual PM2.5 limits and implementing even more stringent second-phase standards starting in 2031.
Beijing, once synonymous with smog, has transformed. The city's annual average PM2.5 concentration fell to 38㎍/㎥ in 2024, down more than 64% from 2013. Days rated "good" for air quality rose to 311, with the excellent-to-good ratio exceeding 80% for the first time.
Statistics show PM2.5 concentrations have steadily declined since 2013 across major urban areas including Beijing-Tianjin-Hebei and the Yangtze River Delta. The Chinese government expects its air pollution reduction policies through 2035 to cut carbon dioxide emissions by more than 7 billion tons.
Incheon Ranks Among World's 10 Most Polluted Cities
Ironically, South Korea's air quality remains under warning at the same time.
According to air quality platform IQAir, Incheon recorded levels "unhealthy for sensitive groups" on the morning of Feb. 20, 2026. That same day, Incheon ranked as the world's 10th most polluted major city. Seoul ranked 11th and Busan 23rd.
Incheon's annual average PM2.5 concentration in 2024 was 19.1㎍/㎥—approximately 3.8 times the World Health Organization's recommended level of 5㎍/㎥.
March is particularly severe. Based on the 10-year average from 2015 to 2025, March's PM2.5 concentration of 26㎍/㎥ is the highest of any month. March also has the most "bad" air quality days at eight.
"China Has an Impact"—But Only About 50%
Where does Korea's fine dust come from? Domestic and international studies indicate that during high-concentration events, approximately 30-50% originates from foreign sources, primarily China. In some months, China's contribution rises to as high as 55%.
Westerly winds carry pollutants from China's eastern industrial zones to the Korean Peninsula. When atmospheric conditions stagnate, those pollutants remain trapped over the peninsula.
However, the remaining 50-70% stems from domestic factors. Internal emission sources including industrial facilities, vehicle exhaust, power plants, heating systems, and agricultural burning remain substantial.
Incheon faces particularly high local emissions due to its concentration of ports, airports, and industrial complexes. Some analyses suggest that salt particles in sea breezes may combine with pollutants to elevate concentrations.
In short, China's influence clearly exists, but it is difficult to attribute everything to China.
In response, the government is launching an all-out spring countermeasure system starting in March, including shutting down up to 29 public coal-fired power plants and strengthening crackdowns on agricultural waste burning.