It is mentioned in the Shastras that one should always wear a pavitra / fresh (clean and washed) cloth while doing pooja everyday. And 'Dhoti' is the purest forms of cloth. Dhoti is the recommended cloth while doing puja, yajna, attending religious ceremonies. It is made to be washed everyday and easily dried up to wear every next day. For the word itself means 'Dho' (wash) + 'ti' (wear fresh next day).
When men stand with their feet together after wearing a dhoti, a shape synonymous to the alphabet ‘W’ is formed in the downward direction of the dhoti. Through its centre point the inherent energy in the dhoti is emitted continuously in the upward direction. Hence, it is perceived subtly that just as Sri Lakshmi stands in the lotus, similarly the person is standing in the sheath of the inherent energy emitted by the dhoti. This upward the inherent energy in the dhoti is transmitted towards the person wearing the dhoti like the plume of smoke arising after putting Dhoop (Black incense) on the live coals during puja and a protective sheath is formed around him. This energy spreads in the body of the person. The presence of negative energies is also reduced.