India had highest number of unvaccinated or under-vaccinated children in the world in 2020 at 3.5 million, according to data by UNICEF. This marked an increase of 1.4 million unprotected children from 2019. The report tracked routine vaccinations for diseases like diphtheria, tetanus and pertussis and said that 10 countries account for 62% of the world's under- or unvaccinated children.