Ten people believed to be responsible for a deadly subway tunnel collapse in east China last year will face prosecution and eleven others have received administrative punishment, local authorities said Tuesday.

A section of a subway tunnel being built in Hangzhou, capital of Zhejiang Province, caved in on Nov. 15, killing 21 construction workers and leaving 24 others injured.

Judicial investigations blamed the tragedy on violations of construction rules, problems in the supporting systems and moulding procedures, and project monitoring failure, according to the Work Safety Supervision Administration of Zhejiang.

Prosecutors will soon bring ten people to court, including the general manager; the chief engineer quality officer of the project; two officials with the contracted monitoring company; two employees of contractor Fourth Bureau of the China Civil Engineering Group Co. Ltd. (CCEG); one officer with the project manager--Hangzhou Subway Group Co. Ltd.; and two officials from Hangzhou's construction quality supervision station, the administration said.

Eleven people, mostly officials with the project contractor and manager, have received administrative penalties.

The accident brought 49.61 million yuan (7.27 million U.S. dollars) in direct economic losses and triggered safety overhauls in subway projects across China.