The European Commission said that it has urged Bulgaria to comply with a ruling of the Court of Justice of the EU in 2017, in relation to the country's failure to adhere to limit values for concentration of PM10 in the ambient air. "While acknowledging that some progress has been made, the Commission is concerned by the slow pace of change and the lack of a coordinated approach between the environmental authorities and the other authorities concerned at national and local levels," the Commission said in its monthly infringements package. Bulgaria has adopted measures related to road traffic, but is still at the planning stage of introducing new requirements for sulphur and ash in coal and briquettes used for domestic heating, as well as other measures, likely to improve air quality. If Bulgaria fails to act upon the Commission's request, the institution may refer the country back to the Court and ask financial sanctions to be imposed. The sanctions may be in the form of a daily penalty, lump sum or both.