Officials in the Chinese capital on Monday said they are mulling over a new program that charges drivers extra congestion fees, which is among a package of measures to curb vehicle emissions.

While the Beijing Municipal Government hopes the program could reduce the number of cars on the road, opponents argue that imposing the charge could be too costly.

"This program is extremely complicated. The facilities and resources put into the program to monitor the entire city may prove to be less effective than expected and would probably aggravate congestion," Niu Fengrui, director of the Institute for Urban and Environmental Studies at the Chinese Academy of Social Sciences, told the Global Times.

Shao Chunfu, professor of urban transportation research at Beijing Jiaotong University, agreed by saying that the core reason behind Beijing's congestion and its air pollution is that the city has been given too many functions by simultaneously being the country's political, cultural and academic centers.

"Its population also keeps growing, putting more pressure on the public system," Shao added.

The city has vowed to cover downtown areas with a network of at least 480 kilometers of bus lanes and introduce a public bicycle rental system to ensure public transportation is used for 60 percent of trips made by residents.

The emissions curbing package, part of an action plan by the Beijing government highlighting its increasing efforts to clean its heavily polluted air, has pledged to reduce the density of PM2.5, the airborne particles less than 2.5 microns in diameter that can pose health risks, by at least 25 percent by 2017.

According to the package, from 2014 the government will also restrict the annual number of new cars hitting the road, and by 2017, the number of vehicles will be under 6 million.

Statistics from the Beijing Traffic Management Bureau show the city had 5.35 million vehicles by the end of July.

By promoting new energy and small displacement vehicles, reducing frequency of vehicle use and strictly enforcing regulations, Beijing has been seeking to reduce total fuel consumption by 5 percent or more from 2012.

The city's traffic management and environmental protection authorities will also roll out traffic control rules for passenger cars by the end of 2013, which will mainly focus on driving restrictions. The rules will be implemented in 2014.

In addition, vehicles from other regions will be subject to more restrictions when they are within Beijing from next year.

The action plan also said the air quality will improve significantly by 2017, with PM2.5 density controlled to 60 micrograms per cubic meter.

Xinhua contributed to this story

Editorial: Congestion fee a necessary step for Beijing