Sustainability work at city scale requires understanding municipal budgets, environmental regulation, climate adaptation planning, and how to move ideas from policy documents into actual infrastructure change. ICLEI's role centres on helping local governments—including Cape Town—build capacity in these areas. What separates credible sustainability support from well-meaning but ineffective work is technical knowledge of municipal systems, access to international best practice, and the ability to broker partnerships between city departments that don't normally talk to each other. The organisation advises on everything from renewable energy procurement to stormwater management to just transition planning as Cape Town navigates climate impacts and economic transformation. Their effectiveness depends on understanding how bureaucracy actually works and how to unlock funding and political will.