Listen to
ISI station chief of Islamabad & DG-FIA Major (R) Muhammad Amir. Go to 4:00 and find out how Karachi Airport was the funnel for illegal migration from India as late as 1990s. Indian's caught a flight to Karachi as transit passengers and then disappeared into the cities huge Mohajir community. What is more this was
officially sanctioned and had powerful people backing it up.
@Desert Fox
Yes but please do note that they came from Pakistan. K-Pk is one of the units that set up the federation we call Pakistan. If K-Pk separated from Pakistan or was separate in 1960s you might have a valid comparison. But here the discussion is migration from outside of the federation. Just to clarify my dad spent some years in Karachi - 1959-62 from where he moved to UK.