Migrant workers have also made important advances in addressing discrimination in economic and social contexts, such as discrimination based on citizenship or immigration status, including "undocumented" status. Migrant domestic workers, migrant construction workers (for example, those working in extractive industries or large-scale infrastructure projects), children, older migrants and migrants in irregular situations are the most vulnerable, often lacking administrative or judicial remedies for their housing claims. Migrant workers and the members of their families frequently face housing conditions characterized by overcrowding, irregular or unregulated rental markets, high exposure to arbitrary changes in the cost of rent or essential services, and substandard living conditions, and can be subject to abuse, in particular when they are undocumented.