There were two reasons that were responsible for the reduced rate after 1921. One is the control over famines and the other is the control of epidemics. Of these two, the second one is more important. The worst killers of the past were different kinds of fever, plague, smallpox, malaria and cholera. The plague in the 1918-19 period killed 12.5 lakh people, 5% of the total population. It was known as Spanish Plague and it was a global killer. Progress in the treatment of this kind of epidemics, preventive vaccinations, improved hygiene and so on helped in the prevention of these killer diseases.
However, even now diseases like malaria, tuberculosis, dysentery, bloody diarrhoea and so on are killing people. But the death rate is not as high as before. In 1994, there was a plague in Surat. In 2006, diseases like dengue fever and chikungunya were reported from different parts of the country. There were also different kinds of bird u in the country not long ago. Death rate was reduced because of effective control of famines. Famines caused heavy loss of life in the past. With their control deaths are reduced.