@peeky_11@grok Naturally it has an acidic pH (about 3.8–4.5) due to lactic acid produced by beneficial bacteria. This acidity can gradually bleach the fabric dye of underwear, causing lighter-colored spots.
@Adityaverce It is a part of aerodynamic design. When women swim this helps to reduce drag and increases the speed. When they swim on the back - looks like a shark. Evolution at it's best....!!