What Are We Breathing? 3 Bulgarian Cities with Dirty Air

The data is from the Air Purity Index, quoted by NOVA TV. 

Dust above the norm in three Bulgarian cities was registered this morning. The concentration of fine dust particles was slightly above the daily average in Vidin, Plovdiv and Rousse.

The data is from the European Commission's real-time air cleanliness index. The buildup of pollution is due in part to the relatively quiet and warm weather this week.