The group of Edinburgh residents, led by lecturer Ashley Lloyd and retired civil servant Alistair MacIntosh, complained diversions brought in because of the trams projects had led to a “phenomenal” rise in traffic in residential streets at the West End, leading to a “pollution timebomb”.
And they claimed the local authority was in breach of an international agreement on access to information.
Experts said the pollution levels were within safe limits. But when they failed to resolve the dispute with the council, the residents took their case to a UN committee.
And now they have been told that one of their complaints has been upheld.
Lawyers in Geneva agreed the council had failed to properly distribute relevant data about air and noise pollution and had failed to provide the campaigners with up-to-date information.
A council spokeswoman said, “We are aware of the ruling and meetings are taking place with residents to discuss this.”