The main features of the informal sector

Describing  the main features of the informal sector, and causes of urban proliferation and urban marginality. How does the informal sector provide direct and indirect subsidy to the formal sector/economy. Work in the informal economy is often characterized by small or undefined work places, unsafe and unhealthy working conditions, low levels of skills and productivity, low or irregular incomes, long working hours and lack of access to information, markets, finance, training and technology.