Many manual scavengers of today can be traced back to the Muslim invasions.
"scholars such as Malkani (1980) among others established that the Bhangis (manual scavengers) were warriors who made captives after they became the prey to the enemy, particularly Muslim invaders..."

So warriors aka kshatriyas, became bhangis due to Islamic force. So much for Islam being "emancipatory"—they created dalits.
"The people who were made captives were
forced to clean indoor latrines and to dispose of the night soil. When these captives were set free, they were not allowed to live in society, and they thus formed a separate caste of Bhangis and continued the work of scavenging.

And manual scavenging become widespread due to the other "emancipators of dalits", the British.
Manual scavenging "was expanded along with the expansion of towns or cities over the last two hundred years... it was legalized and spread across India during the British period."

"...during the British period, there was a surge in number of manual scavengers."
"The British attack on traditional skilled-based occupations (e.g. weaving), and unreasonable taxation on agriculture and the series of famine forced the millions of people, particularly Dalits, to take up manual scavenging as a survival option..."
Imagine how the narrative has been turned on its head by the British being cast as the "emancipators" of Dalits.

Reference:
Manual Scavenging in India: Literature review.
Published by: Dr. Babasaheb Ambedkar Research and Training Institute, BARTI, Pune

Why take offence to this? Are you claiming that Hindu warriors never lost and Islamic invaders never heaped atrocities on them?
It can also be true that some Brahmins were turned untouchable by Islamic conquest, what's the contradiction?
x.com

Of course, in Pakistan, only Hindus and Christians are asked to apply for toilet cleaner jobs. The mentality of the "emancipatory" Islamic invasions is alive and well.
(NYT hides the Hindu part).
nytimes.com