Elisabetta Iob of University of London has written extensively on the refugees who poured into west Punjab during Partition.
Link to research paper: https://repository.royalholloway.ac.uk/file/64d284d0-34e2-0a48-a6a0-2dbb6a83c5ba/7/Elisabetta_Iob_PhD_DIssertation.pdf
Figures and statistics on the number of refugees who fled into West Punjab are widely acknowledged for their unreliability, and still represent a bone of contention between India and Pakistan. The collapse of the administrative machinery threw into confusion any attempt to keep accurate demographic accounts of the comings and goings of persons across the region. In early September 1947, the local correspondent from The Times (London) registered that “more than 1,000,000, and possibly as many as 2,000,000 people” were trekking either eastwards or westwards in search for a safer place in which to live.7 “No reliable estimate” – pinpointed the Governor of West Punjab Francis Mudie a month later – “can be formed of the numbers who have yet to come from East Punjab. It may be 3,000,000. It may be 4,000,000”. Apparently, only 20% of the displaced persons who were temporarily hosted in West Punjab reception camps could be properly identified and recorded. Nevertheless, some kind of a consensus has been reached on the idea that the number of refugees who resettled in West Punjab amounted roughly to 5,500,000.
The 1948 West Punjab Refugee Census reveals that, out of the total refugee population who poured into the Pakistani Punjab, 4,197,000 persons came from the East Punjab Districts; 682,000 from the East Punjab States; 202,600 from the Jammu and Kashmir; 191,600 from Alwar; 91,200 from the Delhi Province; 28,400 the United Provinces; and some other 93,600 from other regions of India. The combination of these latter figures with those of the earlier 1941 Census of India reveals a clearer – albeit still rather cloudy – picture of the districts of origin of those 4,197,000 muhajirs who fled the eastern wing of the Punjab. Torn apart by the 1947 communal violence, the districts of Karpurtala, Gurdaspur, Amritsar, Jullundur and Ferozepore - whose Muslims, by the time of the 1941 Census of India, accounted for respectively 56,4%, 50,2%, 46,5%, 45,6% and 45,1% of the local inhabitants – certainly registered a steady decrease of their Muslim population. Arguably, a fair number of refugees came also from the districts of Ludhiana, Gurgaon, Hoshiarpur, Ambala, Karnal and Faridkot, where Muslims comprised an overall average of 32,6%.