Toxic chemicals from a contaminated site may be a factor in last month's serious sickness among 500 or so students in Changzhou in eastern China. To avoid adverse environmental effects on human health, the country must invest more in soil remediation and create tailored guidelines for decontamination.

Hundreds of thousands of factories have been demolished in China to make way for homes, schools and shopping centres. A national soil survey in 2014 revealed that more than 30% of old industrial land was still polluted (see go.nature.com/a6s5y3; in Chinese). Despite this, the country's total budget for urban soil remediation in 2015 was paltry — roughly equivalent to US$300 million, or just 0.003% of total gross domestic product.

China's current remediation guidelines for urban soil are based on those of the United States (see go.nature.com/lajaaw; in Chinese). However, the US guidelines were developed mainly for contaminated sites that had been built on, so the same standards may not apply to Chinese brownfield redevelopments. For example, China is more likely to overspend on remediating sites that could have high commercial value.

Such selective remediation, combined with the small budget, could limit the decontamination of urban soils and make it unsustainable.