Beijing started to restrict the number of private vehicles on its roads on Thursday to ensure blue skies for a major military parade early next month.
Vehicles will be allowed on the roads based on odd or even license plate numbers up to and including Sept 3, when a grand parade marking the 70th anniversary of China's victory in the War of Resistance against Japanese Aggression will be staged in Tian'anmen Square.
The ban does not apply to ambulances, fire engines, road maintenance vehicles, those carrying foodstuffs, or electric vehicles.
It has been estimated by the transportation authority that the restrictions will cut the use of vehicles by 35 to 50 percent.
Eighty percent of the vehicles used by government bureaus and institutes will also be banned from use during the period.
The Beijing Commission of Transportation said on Thursday that traffic was mildly congested and had been reduced by 30 percent from average levels.
Taxi driver Bai Ming was happy with the restrictions. He said the number of private cars on the roads on Thursday had fallen considerably, bringing him more business.
Environmental protection and traffic authorities carried out inspections at 10 government bureaus to ensure that they were complying with the ban.
The bureaus have 290 vehicles, of which 234 will remain off the roads for 15 days, said Li Kunsheng, head of vehicle exhaust emissions at the Environmental Protection Bureau.
The capital has increased the frequency of buses and subway services to cater to an increase in passengers.
Taxi-hailing app providers such as Didi Kuaidi, China's largest by market share, are giving higher subsidies to drivers to encourage them to use their cars more frequently during the period of the ban.
However, these cars are also barred from the roads based on their license plate numbers.
Beijing has strengthened inspections of vehicles during the ban to see if they comply with air quality improvement measures.
The Ministry of Environmental Protection has monitoring teams in the capital and nearby provinces.
Tianjin is also introducing similar restrictions on vehicles, but only for three days from Sept 1, while polluting companies there will suspend production from Sunday, three days later than those in Beijing.
The ministry said in a statement on Thursday it had found excessive emissions of air pollutants at several companies and coal being used in defiance of restrictions.
For example, some small companies in Xuzhuang, a village in Beijing's Tongzhou district, have been caught using coal-fired boilers.
The ministry and municipal authorities will strengthen their inspections during the restrictions period to improve air quality for the parade.