The parents' complaint, presented on Dec. 1, alleged that a substandard building and inadequate rescue efforts led to unnecessary deaths.

12月1号，家长们在诉讼书中称楼舍质量不合格和救援不力导致了不必要的死亡。

youdao

One police official told the BBC that the collapse appeared to have been caused by the use of substandard building material.

BBC: Mumbai building collapse: Indian police arrest nine

Some parents pointed to poor design and use of substandard building materials as some of the reasons why many schools -- described as "bean-curd dregs buildings" -- collapsed in areas where other buildings were not badly affected.

CNN: Amid rebuilding, scars linger from China quake

Some parents pointed to poor design and use of substandard building materials as some of the reasons why many schools - described as "beancurd dregs buildings" - collapsed in areas where other buildings were not badly affected.

CNN: China quake scars linger amid rebuilding