India and China are not the only states that suffer severe pollution as London's air was reported to be contaminated with greater levels of a harmful pollutant. This caused increase admission in the hosptital due to respiratory infections and early death of the sick and old.

Starting March 10 to March 13, the all of the capital's air quality monitoring site has recorded 'high' or 'very high' during the smog episode.  The minute particles in the air called PM2.5 are specifically hazardous because it has the ability to deeply pierce into the lung tissues are too tiny to be filtered out by the body's immune system. 

The smog's sharp and sudden rise was due to dirty air from some of the industrial areas of Germany, Holland and Poland, including the fertilizers sprayed on farms which gradually move southeast of England on an easterly air flow. As it reached London, the smog was trapped by the sedentary anti-cyclonic conditions and was made even more impure by the everyday emissions from London's vehicles specially the diesel ones, as reported by the Evening Standard.

A report published in 2012 states that the surge in the particles led to increased hospital admissions and the early death of old and sick people. The cause was found out to be associated with the long-term exposure to pollution and lung cancer.

British Lung Foundation founder Professor Sir Malcolm Green, said that inhaling high levels of PM2.5 is comparable to breathing in 'little particles of tar' that can enter the lungs and finds its way to the bloodstream, Business Insider reports.

The founder of the Clean Air in London campaign, Simon Birkett said that, "It's a national disgrace that it's taken an investigation by the Evening Standard to unearth the worst air pollution episode in recent years. Worse, Sadiq Khan and Zac Goldsmith both refused to share our tweeted smog warnings at the time."

Meanwhile, the level of air pollution in Gloucester has been perilously high for the last 10 years. In Painswick Road and Barton Street, the level of nitrogen dioxide has surpassed safety guidelines while the air quality in Priory Road is considered the worst in the whole county, according to the report of Gloucester Citizen.

Air pollution in London has reached the safety guidelines and warns people of the health risks it impose.  Too much of the PM2.5 levels can bring lung diseases specially lung cancer as these tiny particles can penetrate the lungs and the body's immune system has difficulty filtering them out.