Riots often occur in reaction to a perceived grievance or out of dissent.
Riots may be the outcome of a sporting event, although many riots have occurred due to poor working or living conditions, government oppression, conflicts between races or religions.
They were a part of what were known as race riots of the civil rights period.
While a riot may be initially sparked by a specific event, scholars, commentators and commissions have sought to identify the deeper reasons and have identified a number of urban conditions that may underline urban riots.
These urban conditions are often associated with urban decay more generally and may include: discrimination, poverty, high unemployment, poor schools, poor healthcare, housing inadequacy and police brutality and bias.