Bittujee,
There is no concept of untouchability in Islam, so even former Dalits can eat with other Muslims, go to the mosque and share the hookah with other villagers. Now if they stay in their village, they will be known as Muslim Shaikh, a “caste” of Muslim sweepers. But if they move to Karachi or Lahore, send there kids to school, with in two generation there Chura background will be forgotten, and they will integrated into urban Pakistani society. Most Pakistanis have generic surnames like Ali, Hussain, Iqbal etc, which do denote caste.
Can you tell me if the same would apply to Hindu Dalits in India. I am a Tyagi (with bits of Arab and Pathan as well), and when I met my first Hindu Tyagi, he asked me what my gotra was, and I said whats a gotra. So for urban Pakistanis caste is simply not an issue, and even in villages its in decline.
So I stick with my orignal point, the caste system does not exist in Pakistan.