graduated rent; progressive rent increase
A rent system where the amount increases over time according to a predetermined schedule, often used in public housing or long-term leases.
This public housing adopts a graduated rent system.
With graduated rent, the rent increases according to the number of years after moving in.
累進家賃 is a near-synonym also meaning progressive rent, but 傾斜家賃 is more commonly used in the context of public housing policies.
Compound of 傾斜 (けいしゃ, 'incline' or 'slope') and 家賃 (やちん, 'rent'), literally 'sloping rent', referring to a rent that gradually increases.