Christchurch is becoming smoggy again and its unusually high number of high pollution days is being blamed on earthquakes.
The city had 21 high pollution days to the end of July – almost double the number for the same time last winter.
Authorities believe more people are using older wood burners and open fires for heating.
The enforcement agency, Environment Canterbury (ECAN) is not rigorously enforcing clean air regulations because it wants earthquake-affected residents to stay warm.
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