The World's 20 Densest Cities

No. 1
Mumbai, India

Density: 29,650 people per square kilometer

Land area: 484 square kilometers

The largest city in India, Mumbai (formerly Bombay), the capital of the state of Maharashtra, has a population of 14,350,000. It is the financial and entertainment center (Bollywood) of India and home to many multinational companies. A coastal city, Mumbai has large facilities for passenger and freight traffic.

No. 2
Kolkata, India (formerly Calcutta)

Density: 23,900 people per square kilometer

Land area: 531 square kilometers

Kolkata, once India's ruling center under the British Raj, is India's fourth-largest city with a population of 12.7 million. It's now undergoing an economic resurgence that includes financial and information technology businesses. But an outdated transportation system makes for heavy congestion in the city center.

No. 3
Karachi, Pakistan

Density: 18,900 people per square kilometer

Land area: 518 square kilometers

The largest city in Pakistan, Karachi (population 9.8 million) acts as the nation's major seaport. It is the economic center (finance, business services, publishing, education and tourism) and cultural hub of the country.

No. 4
Lagos, Nigeria

Density: 18,150 people per square kilometer

Land area: 738 square kilometers

With 13.4 million people, Lagos is the second-largest city in Africa after Cairo. It is Nigeria's financial center and manufacturing hub, churning out autos, machinery, textiles, processed food and electronic equipment. But city congestion remains a problem.

No. 5
Shenzhen, China

Density: 17,150 people per square kilometer

Land area: 466 square kilometers

Home to 8 million people, the city of Shenzhen is China's second-busiest port after Shanghai. Just a short commute from Hong Kong, it's a large manufacturing center and one of China's primary economic forces.

No. 6
Seoul/Incheon, South Korea

Density: 16,700 people per square kilometer

Land area: 1,049 square kilometers

South Korea's capital and largest city, Seoul checks in with a population of 17.5 million, more than twice that of New York City. It's also far more compact in size, with 3 million registered vehicles spawning enormous traffic congestion.

No. 7
Taipei, Taiwan

Density: 15,200 people per square kilometer

Land area: 376 square kilometers

Taipei is the largest city in Taiwan, with a population of 5.7 million. The city is the center of Taiwan's large and growing technology industry, including the design and manufacture of world class components and products.




No. 8 Chennai, India

Density: 14,350 people per square kilometer

Land area: 414 square kilometers

The city is the capital of the state of Tamil Nadu, with a population of just under 6 million, which make it the fourth-largest in India. A port city and important manufacturing center, Chennai thrives on automobile production and information technology.

No. 9
Bogata, Columbia

Density: 13,500 people per square kilometer

Land area: 518 square kilometers

Bogotá is the capital of Columbia, driven by a population of 7 million strong. It's the country's center of business, banking, insurance and governmental facilities, plus a major area for manufacturing and telecommunications. Its modern transportation system helps alleviate downtown congestion.




No. 10
Shanghai, China

Density: 13,400 people per square kilometer

Land area: 746 square kilometers

A population of 10 million makes Shanghai the largest city in China. It's also the country's economic powerhouse, with financial, industrial, transportation and communication industries all growing. The city boasts the largest container port in the world.

No. 11
Lima, Peru

Density: 11,750 people per square kilometer

Land area: 596 square kilometers

Peru's capital and largest city with a population of 7 million, Lima sits on a South American coast that abuts the major seaport of Callao. Shanty towns and lots of poverty keep transportation in the dark ages and congestion high.




No. 12
Beijing, China

Density: 11,500 people per square kilometer

Land area: 748 square kilometers

Beijing, a city 8.6 million and the nation's capital, is the political, cultural and educational center of China. An increasingly modern transportation system of roads and rail has kept pace with the city's burgeoning economic growth, though it still suffers from big traffic jams and pollution.




No. 13
Delhi, India

Density: 11,050 people per square kilometer

Land area: 1,295 square kilometers

Another national capitol, Delhi's 14.3 million people make it India's second-largest city. Major industries include banking, telecommunications and IT, along with a growing manufacturing capability. Like most of India, Delhi's transportation infrastructure has yet to match its growth.

No. 14
Kinsaha, Congo

Density: 10,650 people per square kilometer

Land area: 469 square kilometers

A river-based city with a population of 5 million, Kinshasa is the governmental and educational center of the Congo, all well as its capital. An antiquated transportation system limits travel opportunity to the rest of the nation.




No. 15
Manila, Philippines

Density: 10,550 people per square kilometer

Land area: 1,399 square kilometers

Manila, the capital and second-largest city in the Philippines, is known as the world's leader in traffic congestion. Its 14.7 million people move around slowly.

No. 16 Tehran, Iran

Density: 10,550 people per square kilometer

Land area: 686 square kilometers

Tehran is Iran's largest city, with just over 7.2 million people. The city dominates the nation's manufacturing sector (electronics, weaponry, chemical and textiles) and acts as the hub of the nation's railroads and highways.




No. 17 Jakarta, Indonesia

Density: 10,500 people per square kilometer

Land area: 1,360 square kilometers

Jakarta is the leading political and economic center of Indonesia. With a population of 14.2 million and growing, the nation's transportation infrastructure has had trouble keeping up. The city has one of the world's worst for traffic congestion problems.

No. 18
Tianjin, China

Density: 10,500 people per square kilometer

Land area: 453 square kilometers

Tianjin is a major Chinese port city, with a population of 4.8 million. As a growing center for manufacturing, petroleum production and salt production, the city is now undergoing major development of its transportation network.




No. 19
Bangalore, India

Density: 10,100 people per square kilometer

Land area: 534 square kilometers

Bangalore is the capital of the Indian state of Karnataka. Its population of 5.4 million makes it India's third-largest city. A growing IT industry has people calling Bangalore the Silicon Valley of India. But for all its growing prosperity, the city still faces large traffic congestion and pollution problems.

No. 20
Ho Chi Minh City, Vietnam

Density: 9,450 people per square kilometer

Land area: 518 square kilometers

The former Saigon is Vietnam's largest city with a population of 4.9 million. Recent years have brought growth in high technology, electronics and light industry. The road and rail systems, still in poor condition, have been hard pressed to keep up.

The World's 10 Most Polluted Places

Summit, Azerbaijan

Potentially affected people: 275,000

Type of pollutants: Organic chemicals, oil, heavy metals, including mercury

Source of pollution: Petrochemical and industrial complexes

A major Soviet industrial center, Summit housed more than 40 factories manufacturing industrial and agricultural chemicals. Cancer rates in Summit are 22% to 51% higher than average incidence rates in the rest of the country.

Lin-fen, China

Potentially affected people: 3,000,000

Type of pollutants: Fly ash, carbon monoxide, nitrogen oxides, sulfur dioxide, volatile organic compounds, arsenic, lead

Source of pollution: Automobile and industrial emissions

Residents of Lin-fen, located in Shanks Province, the heart of China's coal industry, say they choke on coal dust in the evenings. China's State Environmental Protection Administration says Lin-fen has the worst air quality in the country.

Tianjin, China

Potentially affected people: 140,000

Type of pollutants: Lead and other heavy metals

Source of pollution: Mining and processing

Tianjin accounts for half the country's total lead production. Concentrations in air and soils were, respectively, 8.5 times and 10 times national health standards.

Sukinda, India

Potentially affected people: 2,600,000

Type of pollutants: Covalent chromium and other metals

Source of pollution: Chromite mines and processing

Sukinda is home to 97% of India's chromite ore deposits and one of the largest open-cast chromite ore mines in the world. Seventy percent of the area's surface water and 60% of the drinking water contain covalent chromium at more than double national and international standards.

Vapi, India

Potentially affected people: 71,000

Type of pollutants: Chemicals and heavy metals

Source of pollution: Industrial estates

Due to production of petrochemicals, pesticides, pharmaceuticals, textiles, dyes, fertilizers, leather products, paint and chlor-alkali, mercury in Vapi's groundwater is reported to be 96 times higher than the World Health Organization's health standards. In addition, local produce can contain up to 60 times more heavy metals (copper, chromium, cadmium, zinc, nickel, lead, iron) than non-contaminated produce in control groups.

La Oroya, Peru

Potentially affected people: 35,000

Type of pollutants: Lead, copper, zinc and sulfur dioxide

Source of pollution: Heavy metal mining and processing

A mining town in the Peruvian Andes, La Oroya is the site of a poly-metallic smelter owned by the Missouri-based Doe Run Corp. Ninety-nine percent of children living in and around La Oroya have blood lead levels that exceed acceptable limits, according to Peruvian officials. Blacksmith says Doe Run has pledged to curb its toxic emissions.

Dzerzinsk, Russia

Potentially affected people: 300,000

Type of pollutants: Chemicals and toxic byproducts, including Sarin, VX gas, etc. Also lead, phenols

Source of pollution: Cold War-era chemical weapons manufacturing

A significant chemical-manufacturing center, the city was also home to a leaded gasoline factory that produced TEL, a potent toxin. Almost 300,000 tons of chemical waste were improperly disposed of between 1930 and 1998. The Guinness Book of World Records calls Dzerzhinsk the most chemically polluted city in the world.

Norilsk, Russia

Potentially affected people: 134,000

Type of pollutants: Air pollution--particulates, sulfur dioxide, heavy metals (nickel, copper, cobalt, lead, selenium), phenols, hydrogen sulfide

Source of pollution: Major nickel and related metals mining and processing

An industrial city founded in 1935 as a slave labor camp, Norilsk contains the world's largest heavy metals smelting complex, releasing nearly 500 tons each of copper and nickel oxides and 2 million tons of sulfur dioxide into the air. Reports say the snow is black, the air tastes of sulfur and the life expectancy for factory workers is 10 years below the Russian average.

Chernobyl, Ukraine

Potentially affected people: Initially 5.5 million; now disputed numbers

Type of pollutants: Radioactive dust including uranium, plutonium, cesium-137, strontium and other metals

Source of pollution: Meltdown of reactor core, April 26, 1986

A fiery meltdown of the Chernobyl reactor's core released 100 times more radiation than the atom bombs dropped over Hiroshima and Nagasaki. Twenty years later, the 19-mile exclusion zone around the plant remains uninhabitable.

Kabwe, Zambia

Potentially affected people: 255,000

Type of pollutants: Lead, cadmium

Source of pollution: Lead mining and processing

Dispersal in soils of lead, cadmium, copper and zinc extends over a 20-kilometer radius at levels much higher than those recommended by the World Health Organization. In addition to contaminated water, workers live amid dry, dusty, lead-laced soils. On average, children's blood lead levels in Kabwe are five to 10 times the U.S. Environmental Protection Agency's permissible maximum and in many cases are close to those regarded as potentially fatal.

The World's 25 Cleanest Cities

#1 Calgary, Canada

Population: 988,193

Metro area: 5,107 square km

Calgary is the fastest growing city in Canada and has been known in the past as a center for oil and gas. Today it has taken on an added attraction in sports and is becoming more sought by tourists. It has light manufacturing. It was chosen by the Economic Intelligence Unit as a leading city to live in.

#2 Honolulu

Population: 377,260

Metro area: 272 square km

Honolulu is a tourist center and has light manufacturing. It has an excellent public transit system with dedicated bus right of ways that has been singled out for praise by the American Public Transportation Association.

#3 Helsinki, Finland

Population: 564,908

Metro area: 185 square km

Helsinki is Finland's gateway to international trade and communication. It is the political capital of the country and its business, media and cultural center. It has a slightly aged tram and subways system and a light rail commuter system.

#4 Ottawa

Population: 859,704

Metro area: 2,778 square km

Ottawa is Canada's capital and its fourth-largest city. Its economy revolves around a mix of government functions and high tech business. It is called the Silicon Valley of the north. Ottawa has an operating light rail system for transportation.

# 5 Minneapolis

Population: 382,618

Metro area: 151 square km

Minneapolis is the largest city in Minnesota and is clearly a twin city with St. Paul. It is the state's media, business and cultural center. It makes heavy use of bike lanes but also has a well functioning light rail and bus system.

#6 (Tie) Oslo, Norway

Population: 548,411

Metro area: 454 square km

Oslo is Norway's capital and largest city. It is a maritime center for the country, and shipping companies constitute a major business. It has the largest cargo port in Norway.

#7 (Tie) Stockholm, Sweden

Population: 780,818

Metro area: 35 square km

Stockholm is the political and economic capital of Sweden. It specializes in large line of service industries, and the city is nearly devoid of heavy industry. As the country's financial center, it's also where mansion corporations have their headquarters, and it has a renowned transportation system.

#8 (Tie) Zurich, Switzerland

Population: 366,809

Metro area: 91 square km

Zurich is Switzerland's largest city and has a global presence. It is the cultural capital of German-speaking Switzerland. It has been described as the city with the highest quality of life in the world. It enjoys high speed trains, expressways, trams, buses and has a high rate of traffic.

#9 Katsuyama, Japan

Population: 26,961

Metro area: 253 sq km

Katsuyama is a small city in the Fukui Prefecture with a large presence in sports such as skiing and in tourism. It is also well known for its major dinosaur museum. It is a new city, having been founded in 1954.

#10 (Tie) Bern, Switzerland

Population: 127,000

Metro area: 52 square km

The capital of Switzerland, Bern is a cultural and shopping center as well. Its economy, beyond the national governmental functions, is in high tech and financials. It is known for being a major producer of dairy products and chocolate.

# 11 (Tie) Montreal

Population : 1,620,693

Metro area: 393 square km

Montreal, Canada's second-largest city, is a major area for commerce, industry, culture and world affairs. It has a significant presence in electronics, telecommunications and pharmaceuticals. It has a wide array of public transportation, including subways, buses and commuter lines.

#12 (Tie) Vancouver, Canada

Population: 587,891

Metro area: 114 square km

Vancouver, in British Columbia, is Canada's major port and a significant air terminal. It is a center of forest product and mining companies. It has emerged as an important place for software development, biotechnology, and the film industry. It has a broad array of public transportation including trams, interurban trains, ferry services and is mostly clear of motorways.

#13 (Tie) Boston

Population:

Metro area:

#14 (Tie) Lexington, Ky.

Population: 260,512

Metro area: 73 square km

Lexington is known as the Athens of the West and as the Horse Capital. It has moved on from there with some manufacturing, a concentration on technology and considerable educational services. It has a public transit system that is mainly buses, a full range of highways and considerable traffic for a clean city.

#15 (Tie) Pittsburgh

Population: 316,718

Metro area: 151 square km

Pittsburgh is Pennsylvania's second-largest city. Though formerly a steel capital of the U.S., it has turned around and is now into healthcare, education, robotics, technology and financial services. It is a city of bridges with mass transit, buses and Amtrak.

#16 (Tie) Nürnberg, Germany

Population: 500,132

Metro area: 186 square km

A city with a broad array of industries: automotive, electronic, optical and with a strong presence from Siemens. It is deeply involved in industrial research. The city has many motorways, high speed rail, trams, buses and a metro system, and yet it is rather clean.

#17 (Tie) Geneva

Population: 186,526

Metro area: 15 square km

Geneva, the second-largest city in Switzerland is an international services center situated on Lake Geneva with a global presence that involves governmental services, international trade and finance. Its transportation network is most noted for its trolleys and trams, but it also has extensive rail and bus service.

#18 Auckland, New Zealand

Population: 1,260,900

Metro area: 1,086 square km

Auckland to a great extent depends upon an extensive road system for transportation. It is the largest city in New Zealand, the largest port and holds over a quarter of the population. It does, however, have a network of rail lines, buses (limited) and ferry service. It combines commerce and industry with the headquarters of many international corporations.

#19 (Tie) Wellington, New Zealand

Population: 179,446

Metro area: 290 square km

Wellington is the capital of New Zealand and the political center. It has many cultural offerings for the size of the city. It is considered a place of high quality for living. It has a public transit system that includes buses, trains, rail and ferries.

#20 Dublin, Ireland

Population: 505,739

Metro area: 114 square km

Dublin is at the heart of Ireland. It is the capital and seat of government as well as the center of culture, media, communications and high tech labs and educational institutes. Its transportation consists of buses, light rail, walkways and cycle paths. Its most famous manufacturing is beer.

# 21 (Tie) Amsterdam, the Netherlands

Population: 741,329

Metro area: 219 square km

Amsterdam is a major port and a center for large Dutch corporations like Philips and Heineken. It is very bicycle friendly, and the city discourages car traffic in the downtown area. The city has a ring road for car traffic.

#22 (Tie) Toronto

Population: 2,503,281

Metro area: 630 square km

Toronto is the largest city in Canada and situated along Lake Ontario. It is the economic center of a large region and specializes in finance, telecommunications, media and software development. It has the third-largest public transport system in the Western hemisphere.



#23 Lyon, France

Population: 465,300

Metro area: 47 square km

Lyon is the third-largest city in France and is known for its gastronomy as well as its cinema production and business services. It supports a public transit system including a metro, bus lines, train lines and extensive bicycle opportunities.




#24 Copenhagen, Denmark

Population: 503,699

Metro area: 88 square km

Copenhagen is Denmark's capital and largest city with a new bridge to Sweden. It offers programming and other intellectual capital services. It has unique pedestrian walkways and shopping. The city offers public bicycles as well as having trams, bus service and train lines for further out commutes.

#25 (Tie) Kobe, Japan

Population: 1,523,948

Metro area: 550 square km

Kobe is part of the region called Osaka-Kobe-Kyoto. It is a port city and a city of bridges. It has rail lines, expressways and supports some manufacturing. It is known for having headquarters of national and international companies.