Green light district?

"Prostitution originated in Mesopotamia, but in Thailand some part of the law in the U-thong era 628 years ago mentioned prostitutes. They lived in a market outside of the palace wall and included Chinese.

At the end of the King Rama IV, Rattanakosin Era, some part of the bill for protection from diseases mentioned “there should be a lamp for the symbol in front of the house [brothel],” but it did not specific the color. It is assumed that green was used because it is associated with officers. That was the first law controlling prostitutes to follow the law. After that people called brothels a “green lamp place “ and called the prostitute a “lady of the green lamp.”