General Knowledge · Class 12 · Geography and India
Cities and the world
On a summer night a city can be several degrees warmer than the fields around it. Why?
Small test at the end: scroll down to the end of this page for five short questions that check what you have learnt. Tap an answer, then press Check answer. Go to the questions ↓
Jump to: Read first · Try it away from the screen · Check it yourself · Check yourself · For teachers
Read first
6 facts. The questions below make you use them, not just remember them.
- Since about 2007, more than half of the world's people have lived in towns and cities. The United Nations expects about two-thirds to by 2050.
- In India's 2011 Census, about 31% of people lived in towns and cities, and the share keeps rising. Delhi is one of the largest urban areas in the world.
- A megacity is a city area with more than 10 million people. India has several, including Delhi, Mumbai and Kolkata.
- Concrete, roads and roofs soak up heat in the day and give it out at night, and cities have fewer trees and less water to cool them. This is called the urban heat island.
- Chandigarh was planned in the 1950s by the architect Le Corbusier, in numbered sectors with roads, gardens and services planned from the start.
- Public transport moves many people in little space. One full bus can replace dozens of cars on the road.
Offline
Try it away from the screen
On a hot day, measure the temperature (or just feel it with your hand, carefully) on a concrete surface, on grass and under a tree, at the same time. Which is coolest? Write what this means for planning cities.
Make it on paper. Keep it with you. Nothing to upload.
Check it yourself
City rankings ("largest", "most polluted", "most liveable") use different definitions. Check how the city area was defined and where the data came from before you compare.
Check yourself
Five questions about what this page teaches. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
How do you want to answer? You choose, and you can change at any time.
See the answer and why
- A. Street lights warm the air Not this one. Street lights give out very little heat compared with stored heat.
- B. People in cities breathe out more warm air than people living in villages Not this one. Breathing adds very little heat compared with concrete and roads.
- C. Concrete and roads give out heat they stored in the day Correct. Yes. Fewer trees and less water make it worse.
- D. Cities are closer to the Sun Not this one. Cities are not closer to the Sun.
See the answer and why
- A. Shah Jahan Not this one. Shah Jahan built Shahjahanabad (Old Delhi) in the 1600s.
- B. Charles Correa Not this one. Correa was a great Indian architect, but Chandigarh was planned by Le Corbusier.
- C. Edwin Lutyens, who planned New Delhi Not this one. Lutyens planned New Delhi in the 1910s to 1930s.
- D. Le Corbusier Correct. Yes. He planned it in the 1950s.
See the answer and why
- A. 40 Correct. Yes. 60 ÷ 1.5 = 40 cars.
- B. 58.5 Not this one. That takes away instead of dividing.
- C. 60 Not this one. That would be one person per car.
- D. 90 Not this one. That multiplies. Each car carries 1.5 people, so divide.
See the answer and why
- A. A city area with more than 10 million people Correct. Yes. Delhi, Mumbai and Kolkata are megacities.
- B. A city with a metro railway Not this one. Many smaller cities have metros.
- C. Any city that is a state capital Not this one. Many capitals are much smaller than 10 million.
- D. A city that is more than a thousand years old Not this one. Age does not decide it. Population does.
See the answer and why
- A. All of them Not this one. Billions still live in villages.
- B. More than half Correct. Yes. And the share keeps rising.
- C. About one in ten, as most people still farm Not this one. That was true around 1800, not today.
- D. About a quarter Not this one. The share passed one half around 2007.
For teachers and grown-upsWhere the facts come from, and how to use this round.
Sources and notes
- UN World Urbanization Prospects (2018 revision): 55% urban in 2018, 68% projected for 2050. Census 2011: 31.1% urban.
- Urban heat island: discuss trees, water bodies and reflective roofs as fixes. Safety: do not touch very hot surfaces.