Pollution levels in some parts of London are so high they breached acceptable limits for the whole of 2016 in just the first week.
Putney High Street and Knightsbridge are the worst offenders so far according to London Air, an organisation which measures levels of harmful fumes like nitrogen dioxide.
More: London breaches annual air pollution limits in just a WEEK (10. January 2016)
The article also mentions Oxford Circus.
As I've mentioned before, I often suffer from black snot after having visited London.