What does it mean to buy a house in Hangzhou and trigger social security?

You need to provide social security certificate to buy real estate.

Buying a house in Hangzhou triggers social security, which means that when a non-local household registration buys a house in Hangzhou, it is necessary to provide proof that personal income tax and social insurance have been paid in Hangzhou for more than two years in the first three years from the date of purchase, including social insurance paid in other places.