Beijing is covered in smog again, but the Chinese capital isn't the only
big city suffering from this problem at the moment. From Asia to the
Middle East to the Americas, urban dwellers are choking on bad air.
http://www.dw.de/the-worlds-worst-smog-cities/g-17469135
By Julia Vergin, March 3, 2014
Beijing, China
The Chinese capital has been suffering again from smog this winter
with residents forced to wear masks outdoors. But, according to the most
recent figures from the World Health Organization (WHO), the megacity
doesn't even rank among the top 10 cities for smog. Most of the worst
afflicted are smaller cities across the developing world.
Ahwaz, Iran
The city of Ahwaz ranks worst on the WHO's list when it comes to
smog, making it, officially, the city with the dirtiest air in the
world. The reason is the amount of heavy industry in the city, which
uses oil, metals and natural gas in its production processes.
Ulan Bator, Mongolia
Ulan Bator is not only one of the coldest capitals on earth, it's
also the city with the second worst air pollution worldwide. During the
winter months, domestic fireplaces with coal and wood contribute up to
70 percent of the smog in the city.
Lahore, Pakistan
Air pollution is one of Pakistan's main environmental concerns at the
moment. The situation is particularly dramatic in the country's second
largest city, Lahore. The smog is caused primarily by the high volume of
road traffic, rubbish incineration and dust from the surrounding
deserts.
New Delhi, India
In the nearly 10 million-strong city of New Delhi, the number of cars
has increased from 180,000 to 3.5 million in the last 30 years. Still,
it's the city's coal powered plants that are causing the biggest
problem. They contribute to around 80 percent of the total air pollution
in the city.
Riyadh, Saudi Arabia
Sandstorms, like here in Riyadh, can contribute to smog forming
because they increase the amount of particles in the air. In a place
like Saudi Arabia, the intense ultra-violet rays also transform
transport and industry emissions into ozone.
Cairo, Egypt
The poor air quality in Cairo causes a number illnesses among city
residents, like chronic respiratory problems and lung cancer. The reason
for the air pollution is an increase in road traffic and the booming
industrial sector.
Dhaka, Bangladesh
According to a study by the Max-Planck Institute in Mainz, some
15,000 people die every year in Dhaka due to air pollution. Researchers
found the world's highest concentration of sulfur dioxide there.
Moscow, Russia
Even if it looks the same the world over, smog is different,
depending on the city. Smog in Moscow, for instance, is characterized by
high amounts of hydrocarbons. The westerly winds which regularly blow
across Moscow mean that the western part of the city generally has
better air quality.
Mexico City, Mexico
The smog in Mexico City is made worse by the geographical location.
The city is surrounded on three sides by mountains. Due to the high
levels of sulfur dioxide and hydrocarbons in the air, Mexico City was
long considered one of the most polluted cities in the world. The
situation is now improving due to new transport policies and certain
factories being shutdown.
