Smoking in cars that are carrying children has already been banned in some states of Canada, Australia and the US and the whole of South Africa.
Canada's Cancer Advisory Coalition claims the states' bans on smoking in cars have reduced children's exposure to second-hand smoke by 33%.
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The decision was met with outrage and anger by UK cities which were on the shortlist for the prestigious award.
Mr Lewis is one of a number of Labour and Tory MPs under investigation by party officials over allegations of inappropriate conduct.
A jury has failed to reach a verdict in Emile Cilliers' trial on charges of attempting to murder his wife by tampering with her parachute.