Migration within mainland China has led to increased levels of alienation and frustration owing to poor housing, long working hours in poor working conditions and low economic means. China accounts for one-fifth of the total world population and has a diverse ethnic composition. Hong Kong has always been a land of refuge for immigrants. With the adoption of the open door policy in China in the past 30 years, booming economies in cities have attracted billions of migrants seeking opportunities in the cities. The negative impact of migration from rural to city regions extends beyond the migrant workers to their children, as increasing numbers of migrant workers bring their families to the cities. Negative impact associated with migration might also ripple towards the next generation of migrant workers, causing long-lasting mental health problems in the cities of resettlement and the country at large.