I hear that the Mahamantra is from the Kali Santarana Upanishad. Hence, is it okay to chant it anywhere without any conditions, or are there rules associated with chanting these? I am asking this because I have heard that Veda mantras have strict rules.
Sri Sri Muralidhara Swamiji:
Unlike the other Veda Mantras, the Mahamantra has absolutely no rules and restrictions.
Please check these: Excerpts from a discourse by our Sri Sri Muralidhara Swamiji