so I think i can tell
1.when it has degraded or underestimated the substitute or rival's product
2.when it gives false or misleading information on the value of the product.
3.when it is fails to give useful information on the possible reaction or side effects of the production and it is immoral.
EX : There are numerous examples of unethical advertising. can i choose for the example. the one that got in a lot of trouble was when tobacco industries would advertise to children. That was due to the health issues and addiction it proposed to the kid.