Once a world economic champ, China is now bearing the brunt of 2008's global financial crisis and Beijing's subsequent outsized stimulus package, most of which went into fixed asset investments and real estate. What resulted was a property bubble, a heap of bad loans in the banks, and stagnant consumer rates among a majority of Chinese households. Sim Chi Yin photographs Beijing's basement dwellers—a "rat tribe" of underpaid migrant workers who make up one-third of the city's estimated 20 million people.