A new traffic congestion report has surprised many Chinese citizens that Shanghai, rather than Beijing, is the most congested city in China, China News Service reports.

Beijing also fell behind Hangzhou to stand third in the ranking released by AutoNavi, a leading navigation service provider in China.

The ranking was based on a "delay index" worked out through analyzing the data collected from devices mainly installed on taxis and transporters that can record a vehicle's speed, location and driving direction.

The index for Shanghai was 2.16, 2.1 for Hangzhou and 2.09 for Beijing.

An index reading of 2.0 indicates one would spend twice as much time on a trip as on a normal day.

Chongqing, Shenzhen, Guangzhou, Fuzhou, Shenyang, Chengdu and Jinan were also on the top-ten list.

The report shows congestions would worsen either prior to public holidays or during rush hours on workdays.

The area around Caihuying Overpass in Beijing saw the highest congestion index reading of 4.63 nationwide.

Dong Zhenning with AutoNavi said that the traffic condition in Beijing would be worse on the days when vehicles with license plate numbers ending with 4 or 9 - the smallest part of the city's vehicle population - are kept off road.

The report will be issued once a quarter.