Current cities are growing unsustainably into megacities, straining resources and destroying the environment. By 2050, 66% of the world's population will live in urban areas, with the largest growth in India, China, and Nigeria. Cities cannot produce enough clean energy, food, water, or handle the waste they generate without exploiting surrounding lands for hundreds of kilometers. The document proposes developing self-sustaining townships of 5,000-50,000 people that can produce their own clean energy, food, treat waste, and have sustainable housing and transportation to provide for residents' needs locally while protecting the environment. The author's experience living in large cities and sustainable communities motivates supporting sustainable urban planning approaches.