© Shutterstock

1948: Donora, Pennsylvania -

Donora had two big industrial plants, namely the Donora Zinc Works, and American Steel and Wire. Smog was therefore nothing new. But things were a bit different on October 27, 1948.

© Getty Images

1948: Donora, Pennsylvania -

An uncommon weather event trapped air pollution, and the smog lasted until October 31, 1948. The incident claimed the lives of 20 people.

© Getty Images

1948: Donora, Pennsylvania -

It's estimated that 43% of the local population suffered long-term health effects following the smog. The Donora smog kick-started the movement that led to the passing of the Clean Air Act of 1963.

© Getty Images

2010: Moscow, Russia -

In the summer of 2010, the Russian capital endured one of the worst heat waves in the country's history. The heat, air pollution, and the over 550 wildfires combined, contributed to a thick smog forming in the city.

© Getty Images

2010: Moscow, Russia -

As a result, Moscow's daily mortality rate skyrocketed from around 370 people to 700. Particulate matter and smog were 3.4 times over the level of safety, and carbon monoxide at one point reached 6.6 times the acceptable levels.

© Getty Images

2010: Moscow, Russia -

It is estimated that around 104,000 people fled Moscow during this period. Still, by October the stats pointed to 56,000 more deaths, when compared to the previous year.

© Getty Images

19th century: London, England -

Most people will associate smog with London. Indeed, the term was coined by a Dr. Henry Antoine des Voeux in 1905 in a Public Health Congress meeting in London. Smog as such, however, has been around since the Industrial Revolution.

© Getty Images

19th century: London, England -

Records of smog events in the capital go as far back as 1813. This event was followed by many others, namely in 1873, 1880, 1882, 1891, and 1892. Some of these smog events lasted for months!

© Getty Images

19th century: London, England -

The overall death rate is unknown, but one event in particular, in 1873, led to the deaths of 268 people due to smog-induced bronchitis. The poor East End area of the city was the most affected.

© Getty Images

1930: Meuse Valley, Belgium -

Before becoming the idyllic European destination that it is today, in 1930 the area was home to 27 factories, which, of course, polluted the air—a lot.

© Getty Images

1930: Meuse Valley, Belgium -

Between December 3 and 5, the lack of wind and thick mist trapped all the air pollution coming out of the factories, killing 60 people as a result.

© Getty Images

1930: Meuse Valley, Belgium -

It is said that the main culprit was the smog's sulfuric acid content. But other pollutants, including silicon tetra-fluoride, have been blamed for the deaths of people, cattle, and vegetation.

© Shutterstock

1991: London, England -

Yes, it's London again. The 1991 incident happened between December 12 and 15. Traffic-related pollutants, cold weather, and the absence of wind were a recipe for disaster.

© Getty Images

1991: London, England -

Official figures estimate that the 1991 smog killed at least 160 people in the capital, after they were exposed to unsafe levels of nitrogen dioxide in the air.

© Getty Images

1991: London, England -

Years later, however, it has been suggested that the death toll could have been a lot higher, especially in the aftermath.

© Getty Images

2016: China -

In 2016, at least 24 big cities in China were affected by dangerous levels of air pollution. It is estimated that as much as half a billion people were affected by it.

© Getty Images

2016: China -

The air pollution levels were 50 times higher than what the World Health Organization deemed safe.

© Getty Images

2016: China -

Official death numbers are unknown, but a collaborative study between Beijing's Tsinghua University and Boston's Health Effects Institute estimates that the death toll was around 366,000.

© Getty Images

1952: London, England -

The 1952 event, better known as the Great Smog of London, was triggered by an anticyclone (weather phenomenon) that trapped an unsafe, high number of pollutants (including sulfur dioxide). The event lasted for five days, from December 5 to December 9.

© Getty Images

1952: London, England -

The death toll at the time was an estimated 4,000, but more recent research has suggested that numbers might have been closer to 12,000.

© Getty Images

1952: London, England -

Not only did people die, but cattle were also affected. The Great Smog of London eventually led to the creation of legislation to clean up the country's air.

© Getty Images

2005: Malaysia -

In 2005, the country was hit by a thick haze caused by smoke originating from wildfires in the neighboring Indonesian island of Sumatra.

© Getty Images

2005: Malaysia -

The unsafe levels of air pollution led the government to declare a state of emergency. This was the first time it had done so since  September 1997, when a similar event occurred.

© Getty Images

2005: Malaysia -

Greenpeace estimates that the poor air quality in Malaysia is responsible for an estimated 32,000  deaths each year.

© Getty Images

1953 and 1966: New York City -

The two deadliest smogs to ever take place in the Big Apple both occurred in November. First in 1953, and then again in 1966. Numerous incinerators spread across the city polluted the NYC air.

© Getty Images

1953 and 1966: New York City -

The New York Times reported that in the 1960s, deaths from pulmonary emphysema and chronic bronchitis skyrocketed in the city.

© Getty Images

1953 and 1966: New York City -

While numbers do not account for the long-term effects of the 1953 and 1966 events, it is estimated that around 200 people died during each smog incident.

© Getty Images

2013: China -

In January 2013, the country was hit by an earlier smog incident. The haze was so thick that it could be seen from space.

© Getty Images

2013: China -

One hospital alone is said to have admitted over 900 children with respiratory problems during the event.

© Getty Images

2013: China -

Approximately 1.2 million people die every year in China due to exposure to air pollution.

© Getty Images

1948, 1956, 1957, 1950, 1962: London, England -

London has been plagued by many deadly smog events over the 20th century. In November 1948, it's estimated that between 700 and 800 people lost their lives.

© Getty Images

1948, 1956, 1957, 1950, 1962: London, England -

In January 1956, the death toll was around 1,000. Then number of deaths due to the smog in December 1957 was 750.

© Getty Images

1948, 1956, 1957, 1950, 1962: London, England -

It's estimated that between 340 and 700 people died in 1962.

Sources: (Grunge) (The Guardian) (National Geographic) (History Extra) (NPR) (The New York Times) (Greenpeace) (Reuters)

See also: Terrifying facts about pollution from around the world

© Getty Images