Line 2 is an east–west line in the Shanghai Metro network. With a length of nearly , it is the second longest line in the metro system after line 11. Line 2 runs from in the west to in the east, passing Hongqiao Airport, the Huangpu river, and the Lujiazui Financial District in Pudong. With a daily ridership of over 1.9 million, it is the busiest line on the Shanghai Metro. The eastern portion of the line, from to Pudong International Airport, was operated almost independently from the main segment until April 19, 2019, when through service began. The line is colored light green on system maps. History The first section of line 2 was opened on October 28, 1999, from to . This section, which included 12 stations, totaled . A year later, was added to the eastern part of the line, adding . Four new stations, located west of the Zhongshan Park station, opened in December 2006, extending the line to . This section added to the line. Four years later, in preparation for the 2010 Shanghai World Expo, the line was significantly expanded. In February, the Zhangjiang Hi-Tech Park station was rebuilt. In addition, another eastern segment took line 2 to . A month later, the line was extended westward to , adding to the line including a stop at . On April 8, an eastward extension added 8 stations to the line, totaling and taking line 2 to . On July 1, opens to the public with the opening of the railway station of the same name. In October 2006, it was decided to rename three stations on line 2 by the end of the year, adopting a new naming scheme: metro stations, unlike bus stops, are no longer supposed to be named after neighbouring vertical streets, but famous streets and sights in the vicinity, making it easier for visitors to find these places. The renamed stations are Century Avenue (formerly Dongfang Road), East Nanjing Road (formerly Middle Henan Road) and West Nanjing Road (formerly Shimen No. 1 Road). <onlyinclude> Up to April 19, 2019, when an eight-car train started serving the whole line 2 in a regular schedule, the east section of line 2 was served by a four-car fleet. Line 2 had a piecewise service pattern during morning peak hours whereby the suburban segment between Guanglan Road station and Pudong International Airport station is