Big cities

Shanghai, China - 26.3 million people

Crowds walk below neon signs on Nanjing Road. The street is the main shopping district of Shanghai, China, and one of the world's busiest shopping districts. Photo by Getty Images

Many many years ago, Shanghai used to be a small fishing village. But thanks to its location by the southern estuary of the Yangtze River, it has since grown to be the biggest city in China, and one of the largest in the world.

It is also home to the Nanjing Road shopping district, a mix of modern malls and traditional Chinese stores and food outlets. Its 5.5km streets rank alongside Oxford Street in London and the Champs-Élysées in Paris as one of the busiest commercial areas in the world, with one million people shopping there every day.

Delhi, India - 29.3 million people

• Delhi, India - 29.3 million people
• People walk on a busy street in Delhi, India. Photo by Getty Images
• The National Capital Territory of Delhi (NCT) encompasses the city of New Delhi (the nation's capital), as well as several other regional states.
• The city itself has been in existence for over 2,000 years, which brings its own set of problems. Infrastructure is outdated, although there have been many recent road-building projects that have helped to ease traffic.
• Pollution from roads and industry is also a big problem in Delhi, as is the standard of housing. It is estimated that 50 per cent of the population live in sub-standard accommodation.

Tokyo, Japan - 37.4 million people

• Tokyo, Japan - 37.4 million people
• The skyline of Tokyo with the Skytree in the foreground, and Mount Fuji in the distance. Photo by Getty Images
• The heaving metropolis of Tokyo covers just 13,452km2, meaning that there are 2,642 people in each km on average in the whole of the Greater Tokyo Area. This high density obviously presents problems for its residents in terms of living space and travel.
• As to be expected, housing shortages are widespread. Because of this, tiny apartments that measure only 9m2 are becoming increasingly popular amongst younger residents, as they try to locate themselves near to the centre of the city for work.
• Getting around the city is very problematic too. The roads are often completely packed in and around the city. Public transport is also often overcrowded and expensive, although it is almost always on schedule.

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