I have been to Egypt for a few times since about 2005. Many of the diving centers told us there is a legal depth limit of 30m (100ft) for all scuba divers (including CMAS 3* and PADI Dive Master). However, I found a document by "CWDS" (Chamber of Diving & Watersports) which says
The maximum depth for diving with compressed air is 40 meters (if the training qualifications and the experience of the divers allow it)
What is the CWDS? Do the rules from the document apply (i.e., the dive centers just pretend the 30 meter limit to prevent us from diving deeper) or is it true that there is this kind of limit? (Or is it even allowed to go deeper than 40 meters with a single tank of air?)
Note: I do neither care about limits by diving organisations (PADI/CMAS/...) or insurances, nor about limits by using Nitrox (which is free in most centers).
Clarification: This question is about Egypt, whereas my other question is about Turkey. Therefore this is not a duplicate.