Germany will launch a pilot project offering free public transport in five cities to address environmental concerns, local media reported on Tuesday.

Among the cities considering the municipalisation of transport services are the former West German capital, Bonn, and Essen, Reytlingen, Mannheim, and Herrenberg. The municipalities selected have not yet been informed and any additional plans have yet to be communicated to the local authorities, with Bonn’s Mayor Ashok Sridharan only informed of the plan during the last weekend.

Thus far it remains unknown how the cities will cope with the increased demand for free services or improving the technology of their public transport fleet as most cities currently use diesel vehicles. The biggest question is cost, as ticket sales cover half of the operations expenses of the municipal transport bureaus.

Germany received a formal warning from the European Environment Commissioner, Karmenu Vella, for the country’s failure to tackle its Carbon and Nitrogen Oxide emissions. Brussels has given Germany and eight other EU member states a deadline to provide a clear roadmap for improving air quality standards. If they fail to do so, the Commission will take the case to the European Court of Justice.

Germany continues to make heavy use of coal and is unlikely to meet its 2020 emission goals.