Between 1800 and 1920 , life expectancy in India remained in the mid to low twenties , with the largest declines coming in the 1805s and 1910s ; this was because of the Great Famine of 1876 - 1878 , and the Spanish Flu Pandemic of 1918 - 1919 , both of which were responsible for the deaths of up to six and seventeen million Indians respectively ; as well as the presence of other endemic diseases in the region , such as smallpox .