Human, Truck, Transportation, Vehicle, Urban, Building, Nature, Pollution, Fog, Wheel, Machine, Slum, Outdoors, Smoke, Land, Suburb, asia, east asia, china, beijing, peking, city, economy, economic, construction, work, worker, working, job, building, metropolis, national capital, center, district, person, urban area, seat, difficulty, landmass, urban center, economical, capital, excavation, problem, asian country