Kraków’s ban on burning solid fuels plus subsidies for cleaner heating has led to clearer air and better health Kraków’s ban on burning solid fuels plus subsidies for cleaner heating has led to clearer air and better health A s a child, Marcel Mazur had to hold his breath in parts of Kraków thick with “so much smoke you could see and smell it”. Now, as an allergy specialist at Jagiellonian University Medical College who treats patients struggling to breathe, he knows all too well the damage