Past 10 years, Europe is increasing burning waste for generating electricity, and heat for district heating. Especially Sweden is burning 50% of the waste they generate. Waste plastic makes pretty good fuel.
Sweden (5.1) is very close to the world average (4.9 tCO2/capita/year) in fossil CO2 emissions, so they're doing really well for a developed country. (2017 data from Wikipedia.)
There is a caveat in per country carbon accounting. It doesn't include imported goods, nor shipment of those goods. Having said that, Sweden is indeed doing relatively good compared to other developed countries.
Yes, it emits CO2, but is that really a problem? If they didn't burn plastic to produce heat and electricity, they'd likely be burning fossil fuel, which is going to emit probably about the same amount of CO2. Is trash burning really offsetting the use of non-carbon energy sources?