Saudi Arabian officials are looking to find undocumented residents, leading many foreign workers to stay at home. The government has said for years that it would crack down on foreign workers, and Monday's sweeps seem to confirm that. Many businesses and industries slowed down on Monday as workers stayed away from offices and businesses. Saudi Arabia has about 2 to 3 million undocumented workers. The country has the second highest level of youth unemployment in the world, about sub-Saharan Africa.
See "Saudis Crack Down on Foreign Workers", Ellen Knickmeyer, The Wall Street Journal, April 1, 2013