Institutionalized riot systems (IRS) is a term invented by professor Paul Brass in 2004 in his book The Production of Hindu-Muslim Violence in Contemporary India with regards to Indian politics.
This term describes the dramatic production of riots, which Brass has divided into three phases: preparation, activation and explanation.
The most important people in this phase are "fire tenders", who keep Hindu-Muslim tensions alive through various inflammatory and inciting acts.
In this phase another group of people come forward, who lead and address mobs of potential rioters and give a signal to indicate if and when violence should start.
Brass explains that it is because of this system that Hindu-Muslim riots in India often turned into pogroms and massacres of Muslims, in which few Hindus are killed.