Arguably much more controversial advertisements have run on public transit -- including highly sexualized images of women -- but this campaign for period panties is currently being scrutinized for its appropriateness to appear on the New York City subway system.
The controversial campaign comes from THINX, a company that makes period panties for menstruating people with real lives. The period panties can be worn on their own or with tampons, and protect period-having people from leakage, moisture and other menstruation-related inconveniences. The company also donates menstruation products to those in need.
The period panties ad campaign features metaphoric imagery, including a cracked egg and a blood orange. It also talks about menstruation in an upfront way, calling it the "shedding of the uterine lining." It doesn't, however, seem to contravene the rules of polite society -- perhaps people are taking offense to its noticeable absence of blue goop and white tennis skirts.