It means that a large percentage of the population believes in that religion.
Some countries also have a "state religion", which means that the state (i.e. the country) gives some degree of support to a specific religion.
Actually, both the main religion and the historical reasons vary from country to country.
Shintoism became Japan's main religion before.
In the African country of Niger, the main religion is Islam. Other religions that are practiced are Animism and Christianity.
The main language is Spanish and the main religion is Roman Catholicism. But Spain is a multi-cultural country.
Agra is situated in the secular country of India.And as such there is no main religion here.People of all religions live here.
Israel.
Israel.
Denmark is a very unreligious country. Main religion would be Christianity if any.
China has no official or national religion.
london, america, china, australia
Muslim they are the only religion and they take over the whole country :D xx
The largest religion in the US is Christianity but it's a country of many different religions. Church and state are separated, so we are not a country of any one religion.