Megacities and air pollution

12345678
Across
  1. 2. an environmental impact of air pollution
  2. 3. an air pollutant
  3. 5. movement of people from one place to another
  4. 7. a health impact of air pollution
Down
  1. 1. mixture of solid particles and liquid droplets in the air
  2. 4. one of the largest causes of air pollution
  3. 6. large cities with a population of over 10 million
  4. 8. a megacity