In Pakistan’s largest cities, an army of sewage cleaners plunges clogged sewers by hand, often surrounded by cockroaches and without the protection of gloves or masks. The work is essential to maintaining Pakistan’s shoddy sewage system. But it is also highly dangerous, and sometimes costs workers their lives. For sewage cleaning positions, the most hazardous and filthy of jobs, local governments prefer to hire Christians. Last July, one Pakistani newspaper advertisement was so obvious as to say that only Christians need apply for jobs as sewer cleaners.

“I have seen death from very near,” Pakistani street sweeper Michael Sadiq told the New York Times. He described how his friend had died after getting swept away by “putrid black water” in the sewers.

Most Christians in Muslim-majority Pakistan are descendants of lower-caste Hindus, who converted to Christianity by the thousands. The discriminatory legacy of the former Indian caste system haunts them to this day. Often derogatorily called “chuhras” by fellow Pakistanis, these lower-caste Christians are considered “untouchables” or “unclean.”

As some of the poorest people in Pakistan, Christians have limited options for work. They have high illiteracy rates and are often resigned to menial jobs as farmhands, sanitation workers, or street sweepers. But these jobs carry stigmas of their own, reinforcing cultural discrimination against them. According to International Christian Concern, at least 80 percent of Pakistan’s street sweepers, janitors, and sewer workers are Christians.

Street sweeping, like sewage cleaning, is a dangerous job thought to be too demeaning for Muslims. Last month, one Catholic street sweeper in Gujranwala was killed when he was hit by a police car in the road. The family is likely to face pressure to pardon the driver, as officers tried to compensate by giving the family an equivalent of $620 and hiring the man’s son to replace his father.

Cultural discrimination puts Pakistani Christians in real danger—in more ways than one. The vulnerable place that Christians occupy in society also leaves Christian girls disproportionately susceptible to human trafficking. The marginalization of Christians—and the difficulty they face rising out of poverty—makes them easy targets for foreign traffickers, who sell them as brides in China.

The government of Pakistan ought to address the stigmatization of Christians and ensure that religious minorities receive equal treatment in society. Pakistan’s religious discrimination leaves Christians and others vulnerable to real dangers. Pakistan’s government and culture must foster respect for religious freedom, or conditions for religious minorities will never get better.