What is Secularism? How did the Indian Constitution make India a secular state?

Secularism does not confer any privilege or favour on any particular religion.
All religions are treated equally by the law.
(i) Secularism is based on the idea that the state is concerned only with relations among human beings and not with the relation between human beings and God.
(ii) A secular state is one that does not establish any one religion as the official religion.
(iii) Indian secularism keeps equal distance from all religions.
(iv) The state has to be neutral and impartial in dealing with all religions.