The construction of Central Park primarily added to New York City by offering a venue for leisure and recreation within the city. Central Park was designed as an urban oasis where residents could escape the hustle and bustle of city life, enjoy nature, and engage in various recreational activities. While it also served as a gathering place for different communities, including immigrants, its primary purpose was to enhance the quality of life for city dwellers through open green spaces and opportunities for relaxation and recreation.
The other options mentioned, while they could be considered secondary benefits, do not capture the main intention of Central Park's creation. It did not completely eliminate urban pollution, nor was it specifically designed as a meeting place for discussing social issues.