Estimates are from the Pew Research Center’s religious composition of 201 countries and territories, 2010 and 2020, based on more than 2,700 censuses and surveys. Figures are rounded. They measure identification, not how often people practice. In China and Japan many people who take part in Buddhist, folk or Shinto rites are counted as unaffiliated.
County-level religion is not published for most of the world, so those places stay one color for the whole country. Where a census does publish it, open United States counties (2020 congregation rolls) or India districts (2011 identity). Inventing the rest would look precise and be false.
Boundaries are Natural Earth, via world-atlas. A few French overseas departments were split out of France’s outline so they can use their own Pew estimates.
Pew Research Center table