Hindu and Sikh refugees from Pakistan in makeshift camps in eastern Punjab.

An armoured car of the Wiltshire Regiment leaving City Police headquarters on a peace-keeping patrol after communal riots in Amritsar, Punjab, March 1947.

The first train to be attacked was in Amritsar on 6th of March, 1947, when a Muslim mob stopped a train coming from Pathankot in the suburb of Sharifpura and murdered hapless men, women and children. Similar train attacks were carried out on trains coming from Jullundur and Narowal as well.

On the 5th March, when the attack opened, the Muslims attacked only such Hindu-Sikh areas as were mostly surrounded by heavy Muslim zones, such as Sattowali Gali, Gokal New Abadi in Kila Bhangian, Deviwali Gali, Chhaju Misr's Gali, Islamabad, Hall Bazar etc. All this shows pre-planning.

Battle of Amritsar

Sikh refugees

Seems late August or September.

Sikh and Hindu refugees arriving on ships at Bombay Port, 1947.

Also refer to this article for more details on how these refugees arrived from Karachi,

https://www.gatewayhouse.in/bombay-karachi-linked/