Two-wheeled vehicles, particularly high-noise automobiles like motorcycles, will be clamped to stricter controls on their permissible noise increase with an updated policy effective from July, imposing fines of up to 2 million won ($1520) for excessive noise emissions, the Ministry of Environment announced Thursday.

Under the new standard, all two-wheeled vehicles will not be allowed to exceed their noise certification value by 5 decibels. The change aims to put the brakes on vehicle modifications that ramp up the volume of exhaust systems.

Every vehicle comes with its own unique "noise certification test result value" -- a decibel measure of its exhaust noise. It is a key test for manufacturers, ensuring their products meet environmental noise standards before they roll off the production line.

Until now, the ministry’s yardstick for noise was 105 dB for larger vehicles and 102 dB for smaller ones. Critics noted these levels, comparable to a live rock concert or a passing train, were too lenient to have a real impact.

From July, the focus will shift from a one-size-fits-all standard to one that considers each vehicle model's noise profile. If a motorcycle’s noise certification reads 95 dB, it must keep its engine noise under 100 dB to avoid penalties.

The policy change will have the biggest impact on exhaust modification, which is one the major causes of noise pollution. Previously, a motorcycle scoring 80 dB could modify its exhaust to reach up to 105 dB. Under the updated regulations, exceeding 85 dB could result in a fine.

Manufacturers are now obliged to clearly display the noise certification results on the motorcycle's body or frame. If this information is missing or falsely presented, penalties can range from 10 million won to 20 million won.

The push for stricter regulations comes from mounting public outcry over bike noise pollution. Motorcycle noise complaints compiled by the National Police Agency and the Ministry of Environment have accelerated sixfold from 1,496 in 2017 to 9,539 in 2021.