Mumbai is not only one of the most congested cities in the world, but also one of the loudest - mostly thanks to motorists who just can't resist honking their horns, almost constantly. The decibel level regularly crosses the danger limit. So the Mumbai Police, with the help of the agency FCB Interface, decided to do something about it. Traffic signals were turned into Punishing Signals. A decibel meter was rigged up to a selected number of signas - and if the sound level was too high, the red light stayed on. In other words, the more motorists honked, the longer they waited. The police tweeted an amusing film of the project, which quickly became the most liked and shared content in the country. It was even used to educate the future drivers. So this time, the police were right to honk their own horn.