The importance of the urban planner is growing fast in the 21st century, as modern society begins to face issues of increased population growth, climate change and unsustainable development. An urban planner could be considered a green collar professional. The purpose of a professional in the field of urban planning is to optimize the effectiveness of a community's land use and infrastructure. They formulate plans for the development and management of urban and suburban areas on the base of sustainable development trends. The ecological problem associated with urbanization is polluted environment. Over 150 big cities in the world with population from 1 to 15 million suffer from polluted environment. The basic threats are poor air and water quality, insufficient water availability, waste-disposal problems, and high energy consumption which are exacerbated by the increasing population density. The most used methods to avoid threats are promotion of sustainable development, efficient utilization of raw materials, production and conservation of renewable fuel and clean energy (as solar, wind and geothermal energies).