SHANGHAI — Zheng Ruizhen counted herself among the last holdouts on Lufeng Road.

Even as high-rises sprang up in recent years to surround her dilapidated home, Ms. Zheng, a 50-year-old schoolteacher, and her husband, Sun Guojian, held firm. He grew up there. Her school was a 20-minute bicycle ride away. They raised their son there, though he eventually grew so tall that his head grazed the ceiling of his cramped room. When city officials pushed them to sell, they said no.

Then came China’s latest property bubble — a frothy surge in prices that could have global repercussions if it pops.

In August, an unremarkable piece of land around the corner from Ms. Zheng sold for nearly $2,000 a square foot, a national record and nearly three times the average land price in Manhattan. Local officials grew more insistent and threatened to tear down their bathroom.