One Tokyo ward has begun testing an unprecedented project to combat rats using garbage bags infused with the smell of certain herbs.

Chiyoda Ward has faced growing rat problems in recent years, receiving around 200 complaints from residents per year in fiscal 2019 to 2022, a surge from around 50 until fiscal 2018.

The increase may be because "some restaurants do not manage food waste properly and due to a decrease in natural enemies such as crows and cats," a ward official said. The number of complaints is expected to exceed 400 in fiscal 2023, which ends next month.

A downtown area near JR Kanda Station has successfully reduced the number of rats to a certain extent between last summer and autumn through strict garbage disposal rules and enhanced cleaning.

In order to prevent the rat population from growing again, the ward teamed up with a group of waste disposal companies to start a model project using garbage bags that smell of herbs such as mint, which rats are believed to hate.

The project started with four restaurants, having them use the garbage bags and waste disposal firms check whether the bags are later bitten by the rodents.

"One month has passed, but no damage has been confirmed so far," an official at the waste disposal firms' group said.

The project is slated to run until the end of fiscal 2025. The garbage bag "will be introduced to more areas if it proves effective," the ward official said.

The garbage bags being tested to fight Tokyo's rat problem
The garbage bags being tested to fight Tokyo's rat problem | JIJI