[abdullahkhalids]

The majority of the refugees in Pakistan are those from the two Afghanistan invasions by USSR/US, and at their peak were several times the current number.

There was also an internal operation in the last decade to remove the Taliban and such from their strongholds and that caused a lot of innocents to lose their homes.

There were large floods in 2010 and a strong earthquake in 2005 that also destroyed many towns and villages.

And as a historical tidbit, when Mao was in power, a small number of Chinese ran from there and settled in Pakistan.