While it is up to the respective countries to decide on how to meet the NO2-limits that are specified in the EU legislation, a failure to act within two months will mean that the matter will be taken before the Court of Justice of the EU. In the five current cases, most emissions are caused by road traffic which is why proposed measures to counter air pollution include reducing overall traffic volumes and switching to electric cars. 

The European Commission lists respiratory and cardiovascular diseases among the negative impacts of high levels of nitrogen dioxide. 400 000 citizens die prematurely each year as a result of poor air quality.