The deadly toll of city smog

In mid-January 2016 a three-day smog covered London, Nottingham, Leicester and Birmingham. January used to be a peak month for pea-souper smogs. Between 1952 and 1962 these killed nearly 15,000 Londoners and many people in other cities including Glasgow and Manchester. These days our winter smogs are full of nitrogen dioxide and particles from diesel exhaust rather than smoke from coal.

Madrid is the latest European capital to introduce emergency measures to control pollution episodes. If Madrid's new laws applied in London we would have had public health warnings on 19 January, lower speed limits and parking restrictions on 20 January followed by a ban on even-number-plate cars in central areas on 21 January.