The government has talked down claims its plan for the A14 would lead to breaches of air pollution limits.
The Campaign for Better Transport said the proposals, which include creating a toll road between Huntingdon and Cambridge, would "seriously worsen" air quality for people living nearby.
But a Department for Transport spokesman said: "The proposed changes to the A14 will move long-distance traffic away from Huntingdon and help to improve air quality there, not make it worse.
"The government understands the impact a national road project like the A14 can have on air quality, and that is why a full environmental assessment will be completed before any work happens."
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Rather cloudy with brief spells of showery rain. Showers may be locally heavy and thundery by the afternoon.
Colman's mustard has been made in Norwich for years, and has a real kick to it. But now a new milder variety's about to go on the market.
Occasionally bright this evening with a few showers. Then becoming rather cloudy overnight with occasional outbreaks of rain.