[8] The decade between 1911 and 1921 was the only census period in which India's population fell, mostly due to devastation of the Spanish flu pandemic.
[11] The pandemic broke out in Bombay in June 1918,[12][13] with one of the possible routes being via ships carrying troops returning from the First World War in Europe.
[13] The spread of the disease was exacerbated by a failed monsoon and the resultant famine-like conditions, that had left people underfed and weak, and forced them to move into densely populated cities.
"[16] The sanitary commissioner's report for 1918 also noted that all rivers across India were clogged up with bodies,[12][17][18] because of a shortage of firewood for cremation.
The consequent toll of death and misery, and economic fallout brought about by the pandemic led to an increase in emotion against colonial rule.