The Green Salem Business Challenge recently launched its fourth season. The program tries to spur businesses to follow environmentally sound practices and recognizes those that do so. Participating businesses take a pledge to do everything they can to reduce their environmental footprint, adopt green best practices, and increase environmental awareness among their employees, patrons, and the general public. They also take a comprehensive survey in which they list their current and planned green practices. This year’s survey will remain open until April 22. Meanwhile, the Green Salem Business Challenge on Wednesday will wrap up a three-part series of free programs on green topics for local businesses. Wednesday’s event, a panel discussion of local businesses that have made strides in environmental conservation, will be held at 8:30 a.m. in the Enterprise Center at Salem State University, 121 Loring Ave. It will be immediately followed by a tour of Marsh Hall, a campus building that has received LEED Gold certification, a designation that denotes that a building meets high environmental standards.