OTL Canada suffered a similar dilemma when the country realized that it had imported too many Chinese coolies to build the railway. Ever since, British Columbia has struggled to maintain a "whites first" immigration policy.
When the Komogata Maru arrived (1916) with a load of Sikh immigrants, the Royal Canadian Navy prevented them from landing. This merely delayed Sikh immigration.
It was really only after the British Empire collapsed during WW2 that significant numbers of Sikhs or Hindus or Moslems were allowed to immigrate to Canada.
Now some suburbs of Vancouver are dominated by one asian group or another. We refer to Sikhs, Indians, Pakistanis, Bangladeshis, Sri Lankans, etc. collectively as "South Asian."