μεγάλων επαγγελματικών τάξεων που σχετίζονται:
One might be forgiven for failing to spot any problem here. However, there are a couple of traps for the unwary.
First, the probability that, despite the lack of an article in Greek, the English translation would have one: "the ... classes which ...", since the phrase is specified (by the relative clause), and anyway the group is known or could be imagined by the reader. To write simply of "large professional classes involved in tourism" would imply a contrast with small classes (perhaps that they were exempt from the effects), and perhaps that the writer did not have much idea of who these people were (οιωνδήποτε μεγάλων επαγγελματικών τάξεων ...)
Second, επαγγελματικός (professional, vocational, occupational - Stavropoulos) does not have quite the same range of use as professional. In English, the professional classes are doctors, lawyers, bankers, journalists, teachers etc; "professional classes involved in tourism" would be taken as meaning doctors and lawyers etc who worked e.g. for hotels and tour operators. The Greek term would for example include lorry-drivers as an επαγγελματική τάξη που σχετίζεται με τις μεταφορές, but English would not.
While we are discussing επαγγελματικός, a note on επαγγελματική στέγη. Professional roof is not found in English, and you might suspect that anyway, since the meaning of the Greek phrase is not the sum of the individual meanings (There is only a στέγη in the literal sense if the office is on the top floor of the building. For the purposes of local taxation (rates) in Britain, properties (or premises) are divided into residential and business (which includes shops and offices). You could also check office premises, office space and just office.