They're still lowering their target compared to the 2020 target, it's just that pandemic-induced lockdowns reduced the actual emissions even more than planned.

They're still lowering their target compared to the 2020 target, it's just that pandemic-induced lockdowns reduced the actual emissions even more than planned. They're probably not expecting large-scale lockdowns in 2021, so the new target is set under that assumption. Note also that this is about particulate emissions which I think are not subject to the Paris Agreement on climate change. Part of China's strategy to improve air quality is to phase out certain kinds of coal that produce a lot of soot when burning. That helps reduce smog, but the "clean" coal it's replaced with still releases a lot of CO2, so it doesn't really make a difference in terms of global warming.