Pollution

Emissions
Substances given off by human activities or productive processes, which may have adverse external effects.
Urban Economics
The study of the economics of urban areas including factors influencing the growth of towns and metropolitan areas, and challenges unique to conurbations.
Abatement
Reduction in amount, degree, or intensity of an activity, particularly in reference to emissions and pollutants.
Pollution
Damage to the environment by the emission of noxious substances, impacting air, water, and land surfaces.