A casual insult may have become the biggest threat to the rule of India’s prime minister, Narendra Modi.

The labeling of young people as “cockroaches” by a judge galvanized a political movement among them, one that has since its formation absorbed more of India’s angry and disaffected. The result is a growing protest movement that looks to be the most serious challenge to Modi since he took office over a decade ago.

During a hearing in May, Supreme Court Chief Justice Surya Kant referred to some unemployed young people as “cockroaches” and “parasites.” While the judge insisted that his remarks were directed toward a very specific group — those who use fake degrees to enter the legal profession — they antagonized an entire class of people.