The purpose of the campaign called "Dva Kotača od Zaraze Jača ("Bikes Offer Better Protection against Infection" in an unofficial translation) is to encourage more and more residents to ride a bike instead of using cars when commuting to work or visiting Advent events in Zagreb.
The union said today that the campaign would be conducted until 7 January.
Representatives of the cyclists' union cited multiple benefits of using bicycles such as keeping a distance, lessening the pressure on the public transportation services, contributing to efforts to reduce air pollution etc.
The campaign has financially been supported by the city authorities.
Bike commuters are called to share photos on social media networks.