There will be almost an equal number of Muslims and Christians in the world in 35 years, according to a study that says Muslim population is growing faster than any other major religious group.

The study by the Washington-based Pew Research Centre has found that in the coming four decades, Christianity will remain the world's largest religious group, but Islam will see a major increase that will make the two religious groups almost equal in numbers by 2050.

"Muslim populations are expected to grow in absolute number in all regions of the world between 2010 and 2050," says the report titled "The Future of World Religions: Population Growth Projections, 2010-2050".

The Pew Research Centre used demographic trends to project the change by religion and by country.

The study, released on Thursday, was done over the past six years and will continue. Its projections are based on data from more than 2,500 censuses, surveys and population registers from all over the world. It also used mortality and fertility rates, age assessments and patterns of migration and religious switching.

Except the Buddhists, the world's major religions will all see an increase in numbers by 2050. The global Buddhist population will be about the same size it was in 2010, while Hindu and Jewish populations will be larger than they are today.

India will remain a Hindu majority but also will have the largest Muslim population in the world, surpassing Indonesia.

Atheists, agnostics and other people who do not affiliate with any religion -- though increasing in countries such as the US and France -- will make up a declining share of the world's total population, the study says.

The Asia-Pacific region is expected to remain the home of a majority of the world's Muslims. However, the share of the global Muslim population living in several Asian countries, such as Indonesia, Pakistan and Bangladesh, is anticipated to decline between 2010 and 2050.

While 62 percent of the world's Muslims lived in Asia and the Pacific in 2010, 53 percent are projected to live in the region in 2050.

In 2010, Christianity was by far the world's largest religion, with 2.2 billion followers. Islam was the second, with 1.6 billion adherents, or 23 percent of the world's population.