India made history this month when it announced that there were no more cases of polio in the country.

The victory came after years of work by India’s public-health workers. They travelled to the most remote places and the poorest areas in the country. They gave vaccines—medicine that prevents diseases—to 172 million children.

Polio is a viral infection that can paralyze (stop movement in) the body, especially in people’s arms and legs. It can also make people’s breathing difficult is if they have very bad asthma. It can even be fatal.