Authorities in Beijing have unveiled plans to demolish 40 sq km (15 sq miles) of alleged illegal structures, a move set to displace thousands of low-paid migrant workers.
The city's acting mayor said they would "ensure zero increase of such structures".
In November 2017, Beijing tore down buildings that violated safety codes, evicting tens of thousands of workers.
It is unclear how many workers will be displaced this time.
The Chinese capital will also continue to "close small shops operated from illegal openings cut in the wall", according to an annual report released by acting mayor Chen Jining.
Officials believe these are illegal modifications to traditional buildings.
Although the campaign is being presented as a way to improve the city, critics accuse the government of targeting a vulnerable population with few rights.
Millions of migrant workers have moved from the Chinese countryside to cities in recent decades. The World Bank predicts that by 2030, as many as 70% of Chinese people will live in cities.
However, in recent years Beijing has been trying to reduce the population in some parts of the city by 15% to ease pressure on its infrastructure.