Answer:
This is perhaps due to Mexico City's high altitude (7382 ft above sea level), its oxygen levels are 25% lower and fuels do not combust completely. But it is important to mention that proliferation of vehicles, rapid industrial growth and the population boom are considered the main causes of this situation.
Explanation:
Direct= A direct democracy is one in which every citizen votes on all important
Representative=This is where the people elect representatives to run the government
Democracy= ruled by people
Hope this helped <3
Have an amazing day...
-Dignoris :)