Urban livability denotes the degree to which a city provides a secure, healthy, inclusive, accessible, and sustainable atmosphere for residents to live in a high quality of life. It shows how well a city is fulfilling all the physical, social, economic, environmental, and cultural needs of its people.
According to UN-Habitat, a livable city is a city that includes, is safe, is resilient, and is sustainable, as it provides fair access to housing, infrastructure, public opinion, and opportunities.
According to OECD, urban livability means the quality of life based on factors such as housing situation, employment situation, health, education provision, environment, security, and civic engagement.
The Economist Intelligence Unit grades urban livability in five major divisions; stability, healthcare, culture and environment, education, and infrastructure.
Urban livability dimensions:

1. Environmental livability
   Clean air and water
   Urban green spaces and parks
   Climate resilient
   Waste management
   Noise pollution
2. Economic livability
   Job opportunities
   Affordable housing
   Cost of living
   Economic resilience
   Market access
3. Social livability
   Access to quality education
   Healthcare provision
   Social inclusion
   Culture diversity
4. Physical and infrastructure livability
   Efficient public transport
   Availability of cycling and walking infrastructure
   Reliable electricity and water supply
   Digital connectivity
   Quality housing
5. Institutional livability
   Good governance
   Public and community participation in decision making
   Compliance with the laws
   The safety and security.

Major indicators of livable city include:
Dimension Indicator
Housing Affordability, quality, availability
Transport Accessibility, connectivity, travel time
Environment Air quality, green cover, waste processing
Health Number of hospitals, life expectancy, public health quality
Education Literacy rate, number of universities
Crime rate Level of occurrence of crimes
Economy Employment rate, salaries
Governance Transparency of governance
Some indicators of livable city include:
Good governance and communal participation
Affordable and sufficient housing
Effective public transportation
Safe streets and neighborhood
Availability of healthcare and education
Green and open public places
High living standards
Some specific factors that degrade urban livability:
Unplanned urbanized development
Traffic jam
Air and water pollution
Lack of housing and slums
Pollution
Crime rate
Poor infrastructures
Economical inequality
Climate drawbacks
An example of any livable city would be:
Some cities serving as good examples of livable cities would be Vienna, Copenhagen, Singapore, and Melbourne.
Modern urban geography has come to understanding that livability goes beyond just the infrastructure.

Read More:

Urban Growth underpinned by Livability and Sustainable Growth — MENA-Forum

Elements of Urban Design

Entangled Urbanism: Visualising Urban Space as a Network of Interconnected Spaces


Components of the Urban Footprint