Chinese environmental authorities said that the inability to implement certain contingency measures may have contributed to the severe smog that hit Beijing and nearby places during the weekend.
The Ministry of Environmental Protection (MEP) said in a statement issued on Sunday that a variety of violations of the contingency plan set to combat the city's smog problem, the Global Times reported.
According to the statement, the violations included not suspending construction activities as ordered and the illegal burning of garbage, many of which are prevalent in the suburbs.
Meanwhile, hydrocarbon and nitric oxide emissions coming from Beijing's 5.7 million vehicles contributed to around 50 percent of the smog created, the MEP added.
Beijing's Environmental Protection Bureau issued a blue alert for potential smog on Thursday, forecasting that the city's air quality index would go between 200 and 300 for at least a day, the South China Morning Post reported.
On Friday, the alert was elevated to a yellow warning after the index crossed the 300 mark, with some areas registering measurements as high as 350.
Visibility in the city also dropped to under 500 meters as the smog started to thicken.
Chinese Academy Science Institute of Atmospheric Physics researcher Wang Gengchen meanwhile said that pollution coming in from other regions have also contributed to the severity of the smog experienced over the weekend.
He added that the situation could worsen in the coming winter months due to the Siberian cold front not being strong enough to disperse the particles.
The bureau said that air quality will likely improve by Sunday to Monday as a cold front moves in to disperse the smog. However, it could start lowering again by Tuesday due to rising humidity and other factors.
Beijing has put in considerable effort in dealing with its smog problem.
Earlier, the Municipal Transport Commission issued draft regulations stating that only car booking services that have obtained their household registration, as well as having cars of a certain engine displacement, will be allowed to operate.
Officials said that the measures are also meant to deal with the city's significant traffic situation.