Can the waters of the Yamuna and Ganga Rivers cure skin ailments, e.g., psoriasis? If so, how?

Scientifically, the water of the Ganges or Yamuna is not suitable for the treatment of any type of skin disease. If you talk about psoriasis, Vitiligo, or other skin condition, then the best one is Ayurvedic treatment. If there are any diseases, always seek advice from a qualified doctor. Treatment of any skin disease based on religion or superstition is impossible.