You can compare the 1921 return to Singh's 1911 return, pictured here. Sophia Duleep Singh was a Suffragette, famous for campaigning for the right to vote in the United Kingdom. The 1911 census happened before the 1918 Representation of the People Act, which allowed some women to vote. This return shows 'Best information obtainable', as Singh was protesting for women's suffrage by refusing to fill in her census return.
How do these two census returns compare? What can they tell us about Sophia Duleep Singh's life?