70% of noise pollution on Mumbai’s roads is due to excessive honking. After many attempts to curb it, Mumbai Police did what fines couldn’t. They influenced behaviour with an unexpected dash of humour; by turning traffic signals into Punishing Signals. When honking crossed 85 dB, the countdown timer at a signal would reset, making impatient motorists wait more. A film of this solution was cut and tweeted by Mumbai Police. It soon became the most liked and shared topic in India, creating instant results and nationwide chatter.