(CNN) Police in India have come up with an ingenious plan to cut noise pollution -- by making vehicles wait longer for traffic lights to go green if they honk their horns too loudly.
Fed up with the din from car horns in their city, Mumbai Police conducted a trial in November and December last year in which decibel meters were connected to traffic light poles.
If the meters registered noise levels of 85 decibels or over, the lights were reset and stayed red for longer.
As in several other Indian cities, traffic lights in Mumbai display countdown timers.
Pranay Ashok, a police spokesman, told CNN that the experiment took place at a "few important junctions" for 15 minutes a day.
He said a further trial -- at 10 locations -- will be carried out next month. The police hope the concept will then be rolled out to the "entire traffic management system."
Commenting on a video of the initiative that Mumbai Police posted on Twitter at the end of January, Ashok said it showed "the ill effects of this noise pollution." At the time of writing, the video had been watched 3 million times.
The video begins with the police describing Mumbai as "the honking capital of the world," before stating that they had been "itching to do something" about the problem.
In the clip, police name their creation "The Punishing Signal" and offer the following warning to motorists: "Feel free to honk if you don't mind waiting."
The TomTom Traffic Index, which ranks cities according to their congestion, names Mumbai as the world's fourth-most congested city in 2019.
The index estimates that drivers in Mumbai last year lost eight days and 17 hours stuck in traffic. It calculated that someone could read Marcel Proust's "In Search of Lost Time" almost one-and-a-half times during these wasted hours.