Starting from 2025, Grade Four diesel vehicles will be banned from operating inside the central areas of Seoul as part of a plan to drastically cut air pollution.

The policy was announced by Seoul Mayor Oh Se-hoon on Wednesday as part of a comprehensive air quality improvement initiative that aims to halve the capital’s emissions levels by 2030, backed by projects valued at three-point-eight trillion won in investments.

The city aims to reduce the ultra-fine particle density in downtown Seoul from 20 micrograms per cubic meter posted last year to 13 by 2030. 

As such, Grade Four diesel cars will join Grade Five vehicles in being prohibited inside the four main gates from 2025 and throughout the city by 2030, while the ban on the highest-polluting Grade Five diesel vehicles year-round in the city center and seasonally elsewhere will be expanded to a year-round ban throughout Seoul from 2025.

Diesel vehicles categorized as Grade Four generate six times more fine dust than their Grade Three peers, numbering at around 81-thousand units in Seoul. 

Moreover, all vehicles running on internal combustion engines will be banned in central Seoul from 2035 and citywide in 2050.

The city will also accelerate the electric vehicles(EV) transition of delivery motorcycles and trucks by 2026, while implementing measures encouraging EV purchases to attain a one-in-four ratio for EVs by 2030.