This is a very interesting article.
Years ago when we lived in France we encountered people who did business "sous la table". That is "under the table". This article calls the black market "System D". The French word debrouillard (the e has an accent I don't know how to make without a french keyboard).. describes a man who is resourceful and ingenious. People have shortened the Black Market name to System D.
The rise in this system will worry bureaucrats because there is no regulation, no taxes!! According to this article System D is also creating jobs!! One think tank came to the conclusion that half the workers of the world are working in System D!
This is what happens when welfare state governments strangle economies.