Islam is the second-largest religion in South Asia, with more than 600 million Muslims living there, forming about one-third of the region's population. History of Islam in South Asia started along the coastal regions of the Indian subcontinent and Sri Lanka, almost as soon as it started in the Arabian Peninsula, as the Arab traders brought it to South Asia. South Asia has the largest population of Muslims in the world, with about one-third of all Muslims living here. Islam is the dominant religion in half of the South Asian countries (Pakistan, Maldives, Bangladesh and Afghanistan). It is the second largest religion in India and third largest in Sri Lanka and Nepal.