The reason why fine dust from China has decreased. jpg

The primary decisive factor behind the reduction in fine dust from China is thanks to the structural environmental regulations and energy transition policies strongly pursued by the Chinese government.
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​1. Strong Environmental Regulations and Energy Transition
Starting with the 'Air Pollution Prevention and Control Action Plan' in 2013, China has maintained high-intensity air quality improvement measures at a national level for over 10 years.
Decarbonization and heating fuel transition: Coal heating, which was a major culprit of fine dust in the past during winter, has been extensively switched to natural gas or electric heating (coal-to-gas / coal-to-electricity).
Surge in renewable energy: Solar and wind power installation capacities have recorded an unrivaled 1st place globally, rapidly lowering the proportion of thermal power generation.
Rapid adoption of New Energy Vehicles (NEV): Exhaust emission regulations for internal combustion engine vehicles have been significantly strengthened (based on China 6 standards), and the adoption rate of new energy vehicles (EVs, hydrogen vehicles) has been rapidly increased, drastically reducing urban and road emissions.
Forced exit or relocation of polluting companies: Steel mills, chemical plants, cement plants, and other emission-heavy companies around the metropolitan area (the 'Jing-Jin-Ji' region, including Beijing, Tianjin, and Hebei) have been largely closed or relocated to the outskirts.
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​Summary)
​While the decrease in factory operation rates due to economic stagnation played some part, the core is the national-level structural reform policy that reduced coal dependency and introduced massive amounts of electric vehicles and renewable energy. This is because China's average concentration of ultra-fine dust (PM2.5) had already been showing a continuous downward trend even before the COVID-19 pandemic, making it difficult to explain by the effects of economic recession alone.