The number of motorcycles in Hanoi, Vietnam’s capital city with a population of 7.6 million, is expected to reduce in the coming decade as the local government plans to ban the vehicles by 2030 to curb pollution.

In Hanoi, there are about five million motorbikes, which made the air quality in the city deteriorate in recent years, according to a report on devdiscourse.com. In 2016, Capital Hanoi was rated as the second most polluted city in the world after Saraburi, the industrial heartland in Thailand.

There are as many as 2,500 motorbikes per kilometer in Hanoi, reported BBC, citing some local studies. GreenID, a non-governmental organization, said excessive levels of PM2.5, particulate matter that has a diameter of less than 2.5 micrometers, were recorded in 282 days of a year. Until now, there is no underground railway in Vietnam while the first two-storey bus was only launched in Hanoi in June this year.

In early last month, the Hanoi’s People’s Council voted overwhelmingly to limit the use of personal vehicles in the city by 2030 to ease traffic jams and curb pollution, Viet Nam News reported on July 5. It will increase public transport services so that half the population will use it by 2030, up from the current 12%.

The city council also pointed out that the coal-fired power plants, seasonal agricultural burning, construction projects should also be responsible for the deteriorating air quality in Hanoi, which will plant more trees and start encouraging people to use cleaner-burning heaters.

According to the Ministry of Transport, the number of motorbikes in Vietnam was about 45 million motorbikes in late 2016 and will reach 60 million in 2020.