This Zakaz nurkowania icon is made in Material Design style developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 4,300 icons, all in the same style and quality.
It's a logo of a long diagonal line from the upper left to the bottom right. It covers an image of a person scuba diving with their feet in the upper right and their arms in the bottom left with a scuba tank on their back.