PHILADELPHIA - The ban is meant to fight the pervasive litter problem in Philadelphia. It covers nearly a billion plastic bags used each year by Philadelphians. It applies to all retailers, from grocery stores to farmers' markets, and apparel stores to restaurants. However, the ban does not affect the use of paper bags at home. The Philadelphia ban may encourage local retailers to offer reusable bags. After all, providing branded reusable bags to your customers makes good business sense.