In London and across Europe, air pollution is killing more than ten times the number of people dying from road traffic accidents.
The known health effects of air pollution have rocketed in recent years with the World Health Organisation classifying outdoor air pollution as carcinogenic to humans in October 2013 as it did smoking in February 1985.
At its simplest, in public health terms, 'invisible' air pollution is where smoking was thirty years ago in terms of the scale and certainty of the risks and the lack of public understanding of them.
The huge variation in death rates for different death categories across boroughs may raise serious questions about inequalities and the competence and culpability of London authorities.
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The demonstration is due to take place next Saturday in central London ahead of the "emergency" meeting in Brussels to discuss the crisis.