September used-car sales in Beijing rose 12 percent year-on-year to 45,700 units, beating new-car sales for the second straight month, reports Iautos.cn, a Beijing-based used-car Web site.

Sales of new cars in Beijing plunged 44 percent to 40,200 units in September.

With a fleet of 5 million cars and a population of 19 million people, Beijing has the highest car ownership rate among Chinese cities. In 2010, dealerships in Beijing sold 890,000 vehicles.

As Beijing's vehicle population increased, the city developed a reputation for having the worst gridlock of any major city worldwide.

In January, the city set a monthly limit of 20,000 new license plates, for an annual total of 240,000 licenses. If the city sticks to this limit, sales of new cars in Beijing will plunge nearly 75 percent this year.

With traffic congestion worsening, other major Chinese cities such as Guangzhou and Shanghai are expected to take similar measures to control new-car sales.