Answer:
On 27th May 1990, due to the increased riots and violence in sindh, the government of sindh, launched a crack down(curfew) in Hyderabad which was the centre of MQM. Police house to house search began. The muhajirs protested at this treatment and fighting broke out, this is known as puqqa qila massacre; in which 31 women and children were killed, leading to retaliation in Karachi and there were 300 more deaths.