Read this text carefully and answer the questions.

    At the beginning of last century, Fantasia was a sleepy town, and even as recently as the 1950s and early' 60s, there were farms, orchards and vineyards close to our house. Gardens thrived here and you could find an incredible variety of exotic plants and shrubs. Of course, there weren't freeways and there used to be a good transportation system of electric trains. The air was crystal clear and as a young child, I could see the mountains to the north and east almost every day.

    Now, we've got freeways, traffic and pollution. What a shame! If you had seen Fantasia 60 years ago, you would have been amazed. 
Imagine if the city had known what was going to happen? If Fantasia had kept its train system, we might have avoided some of the traffic problems. If the city planners had only thought more about the future, they could have put more money into public transportation. If fewer people had moved to Fantasia Island, the population wouldn't have grown so fast. If Fantasia hadn't grown so fast, we might not have so many problems today. No one anticipated these things; otherwise, we might have been a lot more careful.
 

What is the main idea of the third paragraph?