"herds of cattle in Smithfield reportedly choked to death"

... Visibility was so impaired in some parts of London that pedestrians were unable to see their own feet. Aside from the Underground, transportation was severely restricted. Ambulance services suffered, leaving people to find their own way to hospitals in the smog. Many people simply abandoned their cars on the road. Indoor plays and concerts were cancelled as audiences were unable to see the stage, and crime on the streets increased. There was a spike in deaths and hospitalizations relating to pneumonia and bronchitis, and herds of cattle in Smithfield reportedly choked to death. Though the fog lasted five days, finally lifting on December 9, its severity was not fully appreciated until the registrar general published the number of fatalities a few weeks later, which amounted to about 4,000. The effects of the smog were long-lasting, however, and present-day estimates rank the number of deaths to have been about 12,000. ...