Iron ore slumped back below $100 a ton, snuffing out a rebound, as pessimism over China’s economic prospects again weighed on industrial commodities.

The steel-making material rose almost 10% over the past two weeks on tentative signs that the worst of China’s summer steel rout might be over. But soft manufacturing activity and another round of downbeat news from the country’s property sector stung prices on Monday.

A protracted real estate downturn has squeezed Chinese steel demand and triggered a wave of losses across the industry. At a gathering in Beijing last week, executives from 18 of the country’s biggest producers vowed more “self-discipline” to alleviate a glut of the metal.

Iron ore futures fell 3.9% to $97.10 a ton in Singapore by 3:47 p.m. local time. Steel futures in Shanghai declined.