The most Polluted Cities in the World: Patterns of their Location and Factors that Determine Air Pollution (2017-2020)

The article presents the results of a study of the dynamics of the location and level of air pollution in large cities of the world, special attention is paid to the 30 most polluted cities in the world. It was revealed that for the period 2017–2020, in general, the level of air pollution in cities around the world has decreased. Among the regions of the world in terms of the number of the most polluted cities, South Asia (where 27 cities out of the 30 most polluted cities in the world are located), East Asia and Southeast Asia stand out. Among the countries of the world in terms of the number of the most polluted cities in the world, India (where 22 cities from the 30 most polluted cities in the world are located), China, Pakistan, Bangladesh and Indonesia stand out. The leading factors of the formation of the ecological situation in the most polluted cities of the world, depending on their localization, have been identified: 1) emissions of vehicles (in all cities); 2) emissions from industrial sites and factories (in all cities); 3) meteorological conditions (in the cities of India); 4) features of economic activity - the presence of artisanal kilns for baking bricks (in the cities of Bangladesh and Pakistan); 5) burning of waste and stubble of agricultural crops (in the cities of India); 6) transboundary pollution (in the cities of India and Pakistan). Options for improving the ecological situation in cities are proposed: 1) improve the regulation of emissions from vehicles and industrial sites and factories at the local level; 2) prioritize sustainable and clean energy sources; 3) promote low-cost, active and carbon-neutral travel options; 4) use technologies and initiatives of smart cities.