They often use an unattenuated (live) vaccine in undeveloped countries because of refrigeration and transportation issues. Transitory and isolated populations are a problem. Fear and superstition also limit vaccination efforts.

Originally the West had to use this more dangerous vaccine, but still managed to eradicate polio.

By 2016, polio was nearly eradicated in India:

India completed a full 5 years as a “polio-free nation” on January 13, 2016. It was a remarkable feat considering the odds against achieving this status. The Global Polio Eradication Initiative (GPEI) considered India to be the most difficult region of the world to eliminate wild polio virus (WPV) transmission and then maintain that status for 5 years. https://pediatrics.aappublications.org/content/138/4/e20160461

They often use an unattenuated vaccine in undeveloped countries because of refrigeration and transportation issues. Transitory and isolated populations are a problem. Fear and superstition also limit vaccination efforts.

Originally the West had to use this more dangerous vaccine, but still managed to eradicate polio.

By 2016, polio was nearly eradicated in India:

India completed a full 5 years as a “polio-free nation” on January 13, 2016. It was a remarkable feat considering the odds against achieving this status. The Global Polio Eradication Initiative (GPEI) considered India to be the most difficult region of the world to eliminate wild polio virus (WPV) transmission and then maintain that status for 5 years. https://pediatrics.aappublications.org/content/138/4/e20160461