“Modi has said he wants economic development for everyone,” Mr. Akhtar said. “This job has allowed my children to eat and go to school. All we want is peace, to be allowed to work in peace.”

Life in this strip of villages had changed drastically with the advent of the meat factories a decade ago, people here said. Mud huts, which routinely collapsed during the monsoon, had been replaced by solid brick buildings. Men working in the factories had begun to invest in motor scooters. Women had been pulled into the work force, abruptly doubling family incomes.

Mr. Akhtar said he could afford to remain in Uttar Pradesh for two weeks without pay, and then he would have no choice but to return to his native village, along with thousands of other migrant workers who gravitated here for jobs. Other men clustered around him — peddlers, truck dispatchers, factory supervisors, cleaners, butchers. Some of them warned that further pressure on the industry would lead to violence.

“Suppose that there are five people in a single family working here, and they are all jobless,” said Muhammad Majid, 21, who has been working at a slaughterhouse since he was 15. “If there are riots, they will be difficult to contain.”

Most Indians were not aware that buffalo meat overtook rice as the country’s largest food export in 2015.

The industry’s growth has gone unnoticed mainly because of religious sensitivities: Meatpacking, like leather, is a sector dominated by Muslims, who make up around 19 percent of this state’s population. Though it is legal to slaughter buffalo when they are old and can no longer give milk, right-wing Hindu groups have long suggested that cows were being spirited into the facilities, and they have routinely intercepted supply vehicles for aggressive searches.