What are the limits of a man's awrah (private parts that must be covered), and is it permissible for him to enter swimming pools on a day designated for men if there are individuals inside the pool who are not wearing clothing that covers their awrah?

The majority of scholars define the awrah (private parts) as being between the navel and the knee, citing prophetic hadiths that prohibit uncovering the thigh and consider it part of the awrah. There is no harm in entering a swimming pool if it is free of women, and the men present are covering their awrah, and you yourself are covering your awrah.