“Fine dust free” – The first European public environmental campaign by mobile phone.Basic situation:The city of Graz has the highest fine dust pollution level in AustriaRoad traffic is one of the main causes of this environmental problemGoal of the City Graz:To encourage car drivers to switch to public transport.Target group: private car owners Graz – 100,000Success: 10,430 registered users 10% responseConcept: All user interaction by mobile phones – no paper ticketsThe user receives a free ticket for public transport on his mobile phone if the fine dust level exceeds the threshold.