Slitherine

Does anyone know what HELLS mean city names displayed in red? I've reached the supposition that city names displayed in blue want to mean that there's a new population icon (in white) in the city display. This could have been used for something useful, but at least is more or less clear. But I've driven myself crazy attempting to adivinate (cause logic has no relation at all with this) what could mean badly rotten bastards red city names.
Of course, nothing about this can be read in the game printed manual enclosed with the game box. The manual only explains that which was obvious. Difficult matters are just for you. Disadvantages of purchasing legal software; I will consider it next time I buy a game.

A city name in red means the city has grown as much as is possible for a city of that size, and there are no unemployed people.

Thousand thanks, Sum 1 won. I think I could never known it by myself. I was somewhat worried cause I have most of my cities in red, and I could't suppose it had a good meaning (done all you could do for that city), not a bad one. Thanks a lot.

By the way, do you know any cheat code for this game?