Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: Criminal landlords and letting agents who exploit tenants in London are to be "named and shamed" on an online database, the mayor has announced.

London criminal landlords to be 'named and shamed' online