2008 Sichuan earthquake
The central government estimates that over 7,000 inadequately engineered schoolrooms collapsed in the earthquake. Chinese citizens have since invented a catch phrase: "tofu-dregs schoolhouses" (Chinese: 豆腐渣校舍), to mock both the quality and the quantity of these inferior constructions that killed so many school children. Due to the one-child policy, many families lost their only child when schools in the region collapsed during the earthquake. Consequently, Sichuan provincial and local officials have lifted the restriction for families whose only child was either killed or severely injured in the disaster. So-called "illegal children" under 18 years of age may be registered as legal replacements for their dead siblings; if the dead child was illegal, no further outstanding fines would apply. Reimbursement would not, however, be offered for fines that were already levied.

Q: Why did so many schools collapse during the earthquake?
inadequately engineered