Asia Bibi was on death row for blasphemy, after offering drinking water which she, as a Christian, was considered to have made “unclean” by her touch. She got into an argument over this.
Many Pakistani Christians – who are about 2% of the population – are children of converts to Christianity from the downtrodden “untouchable” Hindu tribal caste – they are sometimes called “chuhra” (a modern equivalent might be something like “toilet cleaner”). Their families converted in the late 19th to early 20th centuries in the villages of what is now the central Punjab of Pakistan. This “untouchable” caste status is at the root of several blasphemy charges against Christians.
Also synonymous with “low born”, “filthy”, “deprived of morals and values”, of “low intellect”, and condemned to suffer for sinful past incarnations is their expected work as “sweepers”, also known as “janitors” in the Indian subcontinent.