Following this period of rapid development and environmental degradation, the ecosystem began to receive notable attention from conservation groups in the 1970s. Internationally, UNESCO and the Ramsar Convention designated the Everglades a Wetland Area of Global Importance. The construction of a large airport north of Everglades National Park was blocked when an environmental study found that it would severely damage the South Florida ecosystem. With heightened awareness and appreciation of the region, restoration began in the 1980s with the removal of a canal that had straightened the Kissimmee River. However, development and sustainability concerns have remained pertinent in the region. The deterioration of the Everglades, including poor water quality in Lake Okeechobee, was linked to the diminishing quality of life in South Florida's urban areas. In 2000 the Comprehensive Everglades Restoration Plan was approved by Congress to combat these problems, which at that time was considered the most expensive and comprehensive environmental restoration attempt in history; however, implementation faced political complications.