BEIJING, Dec. 14 -- Authorities are mulling whether to raise the Beijing subway fare of two yuan (about 0.33 U.S. dollars), which has long been the country's lowest.

Fares could be adjusted in rush hours to help disperse the flow of passengers, according to a working draft released by the Beijing Municipal Government on Friday.

Beijing's two-yuan fee, which allows passengers to ride on any line and make transfers, is lower than 14 years ago, when it was hiked to three yuan in 1999. But the fare was adjusted back to two yuan in 2007.

The draft did not specify how much the fare would be raised or when the revision might be made.

Beijing currently has 456 kilometers of subway lines in operation, carrying 10 million passengers daily.