Caerphilly street is 'most polluted' in UK outside London
Air pollution is a "public health crisis" and needs to be tackled urgently, a health agency has warned.
Public Health Wales (PHW) said it was second only to smoking and more of a concern than obesity and alcohol.
Its figures show air pollution causes 2,000 deaths a year - 6% of Wales' total.
The most blighted areas include Hafodyrynys Road in Crumlin, Caerphilly, the UK's most polluted street outside London.