Both petrol and diesel cars may come into this category, and it is estimated that up to 10,000 vehicles a day could be penalised.

Pollutants, including nitrogen oxide, are thought to be responsible for up to 10,000 premature deaths in London every year, as well as a rise in health problems including asthma and heart disease. Air pollution levels in London are higher than in Beijing, China, and the city is routinely criticised for exceeding limits set by the European Commission.

Mr Khan, who was elected as Mayor of London in May 2016, is a strong supporter of both greener transportation and environmental issues. His policies include a freeze on ticket prices for public transport within the city, and investment into the network.

The toxicity charge is not without its critics,Plains Village period

The Plains Village period or the Plains Village tradition is an archaeological period on the Great Plains from North Dakota down to Texas, spanning approximately 900/950 to 1780/1850 CE.

On the west and east, Plains villagers were bounded by the Rocky Mountains and the Eastern Woodlands. Prior to the reintroduction of the horse and contact with Europeans and Africans, Plains Indians were mostly semi-sedentary; they typically farmed in villages and hunted bison in temporary camps. Depending upon the region, their architecture included grass houses; stone-lined, semi-subterranean pit-houses; and earth lodges. Bison scapula hoes were important tools in farming crops such as maize, beans, and squash. People made ceramic pots for cooking and storage.

The people of the earlier parts of this archaeological period spoke Siouan languages and Caddoan