Seventeen workers are missing after a subway tunnel they were building in Hangzhou, Zhejiang province, caved in, killing at least three people, AP reported, citing state media. The accident was caused by the collapse of a 75-meter-wide section of road above the construction site on Saturday. By Sunday night, rescuers were still pumping water that had seeped into the tunnel from a nearby river. "There is a slim chance for the survival of trapped workers because of heavy flooding in the crater," state media quoted Wang Guangrong, spokesman for the rescue team, as saying on Sunday. Poor construction quality stemming from bad planning, shoddy work or theft of materials remains a chronic problem in China. More than a dozen Chinese cities have received approval to build new subway systems in recent years.