From China Digital Space
拆哪 (chāi nǎ) Demolish it; literally “Where to demolish?”forcibly evicting people from their homes to build on the land. Anger over forced demolition lead the people of Wukan, Guangdong to fight the local government, eventually laying siege to their village in December 2011.
Nǎ 哪 means “where” or “which.” Hence, “chāi nǎ” also sounds like the question, “Demolish where?” and mocks the ubiquity of demolition.
All over China, one sees “拆” spray-painted on the sides of buildings slated for demolition. People who have had their homes demolished are called chāiqiānhù 拆迁户.
Victor Mair has a collection of nicknames for China, including chāi nǎ, at Language Log.