Complex sentence: The act became in action in 1948, and it gave citizenship to about 5,000 Indian Tamils and more than 700,000 population (about 11%) were either non-citizens of Ceylon or became stateless.
Split into simpler sentences: The act became practice in 1948, and it resulted to grant citizenship to about 5,000 Indian Tamils. However, more than 700,000 people (about 11%) were either non-citizens of Ceylon or became stateless.