In 1963, the world's main reservoirs of smallpox were found in Asia. 75,000 cases and 23,000 deaths were reported there. Most of these cases were in India. The smallpox endemic areas in Asia were a threat not only to the countries in which they were found but to the whole world, as shown by the outbreaks which followed in Europe.
The biggest campaign against smallpox in 1963 was the Indian national eradication programme which aimed at vaccinating the entire population or more than 400 million people within two years. The programme started at the end of 1962, and by March 1964 224,500,000 vaccinations were performed, using freeze-dried vaccine recommended by WHO for use in the tropics. In New Delhi, a special propaganda campaign was launched. Public meetings were held, processions went through the city shouting slogans asking people to get vaccinated by several teams of doctors from the Delhi Department of Health, during a one-week campaign.