A process of decline in the influence of religions is called:-

Secularization

In the modern west, secularisation has usually meant a process of decline in the influence of religion. It has been an assumption of all theorists of modernisation that modern societies become increasingly secular. Indicators of secularisation have referred to levels of involvement with religious organisations (such as rates of church attendance), the social and material influence of religious organisations, and the degree to which people hold religious beliefs. Recent years have, however, seen an unprecedented growth of religious consciousness and conflict world over.