The 16 worst hotspots for deadly toxic air are all in London 10 years after Ella Adoo-Kissi-Debrah's death. The child died at the age of nine due to air pollution. A press release shared by London's Mayor Sadiq Khan reported that young Londoners are growing-up with stunted lungs and toxic air is leading to the premature deaths of around 4,000 people every year.

This footage shows the London skyline being obscured by heavy air pollution.

Concentrations of carbon dioxide in the Earth's atmosphere surged to a record high in 2016, according to figures from the World Meteorological Organization.

Atmospheric levels of CO2 surged to 403.33ppm in 2016, compared to 400ppm in 2015.

The WMO said human activity and El Nino were responsible.

"Without rapid cuts in CO2 and other greenhouse gas emissions, we will be heading for dangerous temperature increases by the end of this century, well above the target set by the Paris climate change agreement," said WMO Secretary-General Petteri Taalas. "Future generations will inherit a much more inhospitable planet," he said.

Heavy air pollution obscures much of Central London in a thin mist of smoggy dust. Footage taken from Wimbledon.