• 2. The introduction of contaminants into the natural environment that cause adverse change
  • 3. City that issued first pollution red alert as smog engulfed the capital
  • 5. A type of air pollutant. The word was coined in the early 20th century as a portmanteau of the words smoke and fog
  • 6. The capital city of a Latin American country introduced the Hoy No Circula (‘today it doesn’t circulate’) in 1989 to combat rampant air pollution
  • 7. A layer of gases surrounding a planet or other material body of sufficient mass


  • 1. This Roman statesman implemented a temporary road space rationing in Rome in 45 BC
  • 4. Capital city set in place the scheme of Pico y Placa (‘peak and plate’). This policy banned cars from driving during the peak traffic hour, two days per week