Top management shows leadership of, and commitment to, the environmental management system: it is accountable for how effective the system is; it makes sure the environmental policy and objectives are set and fit the organization's context and strategic direction; it builds the system's requirements into business processes; it makes sure the system has the resources it needs; it explains why effective environmental management matters and why the system's requirements must be met; it makes sure the system delivers its intended outcomes; it directs and supports people so they help the system work; it promotes continual improvement; and it supports other relevant managers in showing leadership in their own areas.
This control maps to 36 controls across 27 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.