A TRAIN on Metro Line 2 was stuck in a tunnel yesterday for about 20 minutes due to a technical glitch, prompting passengers to complain about the carriages being stuffy — saying the air conditioning failed in the middle of the heatwave hitting the city.

The issue also meant trains from Zhangjiang High Technology Park to Shanghai Science and Technology stations had to run at slower speeds.

The Metro operator announced the problem on its Weibo account about 8:45am and said by 9:30am the issue was resolved. But many netizens complained it was stuffy in the carriages and the air conditioning was not working.

“Everyone onboard was sweating,” a netizen named “lidaweitongxie” posted on the Metro operator’s Weibo account. “Some people even called the police and one opened the carriage door to feel better. The train stopped in the tunnel for more than 20 minutes.” The Metro operator told Shanghai Daily the air conditioning was working but conditions were affected because the rush hour train was packed.