If you recall the financial crisis it started with subprime which was small part of the housing loan market.
That was the tip of the iceberg
Once the problem start and property price start falling buyers use the escape clause in the mortgages that releases them from their obligation once they allow banks to foreclosure. Basically they dump their property to the bank and walk away when the property had negative equity. Once they abandon the property they neighborhood become like ghost towns and the property became worthless selling for a fraction.
Above is unlikely to happen in China.
What is happening is the crisis is spreading from Evengrade to blue chip developers like Vanke who saw the bonds plunge last week.
Situation is turning very risky.
I, being poor, have only my dreams; I have spread my dreams under your feet; Tread softly because you tread on my dreams.