Both : 

• Unacceptable: the use of sneakers, sandals, jeans, shorts, t- shirts of any type, sweatshirts, or any non-formal clothing is strictly prohibited; as well as the use of some informal accessories including hats (unless for religious purposes), sunglasses, and caps; clothing that exposes excessive bare skin, exhibits undergarments, or is in any other way revealing is inappropriate.

Men :

• Acceptable: It’s obligatory to wear a dress shirt (long or short sleeve) and dress pants, tie or bow tie, belt, socks and dress shoes. The size and color is the delegate’s preference.
• Unacceptable: unbuttoned shirts and sleeves rolled up.

Women:

• Acceptable: skirts or dresses with the length below the knees.
• Unacceptable: miniskirts, low cut blouses, leggings or tight pants.