Hi Ocelotte,

what Jakka might be trying to say is that you created a changeset with a large bounding box covering the continent from Switzerland to Ireland. This needn't happen and in most cases is kind of bothering the people trying to do some Quality Assurance of the map data. More info here: https://wiki.openstreetmap.org/wiki/Changeset#Geographical_size_of_changesets

You probably didn't even notice because you use the neat little app "StreetComplete". It's a really helpful tool to add data to existing features and it's really nice of you to run around using it. To keep large change sets from happening do one of these things:
Enable auto upload of your changes. This will create one small changeset for every answer you give.
Hit the upload button once you're done in one "city". This creates one change set for each category of questions you answered and each of those change sets will only cover the city you just worked in.

Thanks and safe travels
silversurfer83