Urban dualism refers to the existence of two different urban domains or systems within the same urban area. It is usually seen in developing nations, wherein modern urban structures occur side by side with their traditional kind. Thus, urban dualism results in huge socio-economic inequalities.
Urban dualism can be characterised by:

Economic Dualism
Formal economy: organised industries, corporate institutions, banking, and modern services offering secure job opportunities. In this instance, employment is characterized by technical and economic resilience.
Informal economy: street vendors, daily laborers, home enterprises, domestic workers, and informal markets with low incomes and insecurity in jobs.

Spatial Dualism
Planned neighborhoods, mainstream business regions, gated communities, etc. co-exist with slums, squatter settlements, and unauthorized neighborhoods. Accessibility of urban services varies a lot from area to area.

Social Dualism
There are significant imbalances in terms of incomes, education, health care, and quality of life.
The wealthy group enjoys a high quality of housing and services; poor people live in insufficient conditions.

Infrastructure Dualism

In developed areas, residents have reliable roods, water supply, sewage systems, and public transport services. Informal areas do not normally have such basic urban services.

Reasons for urban dualism

• Colonisation created segregated urban areas.
• Urbanization and rural migrations to cities.
• Industrialization in the condition of underdeveloped housing and infrastructure.
• Unequal economic development.
• Poor urban planning and management.

Examples.
Some Indian cities: Delhi, Mumbai, Kolkata, Bengaluru, Aligarh.
Brazil: São Paulo and Rio de Janeiro.
South Africa: Cape Town, Johannesburg.

Advantages.
The informal sector provides job opportunities for millions of urban migrants
Offers cheap goods and services.

Disadvantages of urban dualism.
Growing economic divide.
Slum expansion and informal settlements.
Social exclusion.
Theoretical perspectives.
W. Arthur Lewis’s Economic Dualism Theory
Colonial urban dualism.
Dependency theory.

Read More: