Rules applying to outdoor fires during winter in Napier and Hastings air sheds began this week.
No outdoor burning is permitted in these zones until after August 31.
Hawke's Bay Regional Council pollution response enforcement team leader Mike Alebardi said: "The burning rules aim to clean up the winter air because of the inversion layer that forms over the cities on cold, windless days and traps smoke near the ground where it's a health hazard."
Just a few exceptions are allowed for in the rules.
Fires are permitted for burning orchard or vineyard material when food production trees are being replaced with others, when shelterbelts need to be removed for redevelopment or when landowners need to control disease, Mr Alebardi said. Barbecue or hangi fires are also permitted.