What are the levels of obligatory forbidding of evil in public places?

Question:
Honorable Shaykh, may Allah grant you success. A questioner says: Violations of the Shari'ah are common in public places, such as the free mixing of men and women, women displaying their adornment, and young people not adhering to the Shari'ah dress code, where they expose their thighs or half of their thighs. His question is: What is the obligatory forbidding in this case? And what is your advice regarding how to deal with them?

Answer:
Forbidding evil has three levels: with the tongue, with the hand, as the Prophet (peace and blessings be upon him) explained. With the hand, if he has authority. If he does not have authority, then with the tongue, through advice and explanation. If he does not have the ability to explain with the tongue, he forbids the evil with his heart, and he withdraws from the place and stays away from it, and does not go to it.