Mexico City on Thursday lifted a three-day-old pollution alert that had kept nearly half the city's 5.5 million vehicles off the streets.

The restriction against 40 percent of the vehicles ended because steady winds dispersed the smog of recent days and improved air quality, the city's environmental department said.

It was the second time since last month that the government declared the alert because air pollution exceeded acceptable limits.

The Chamber of Small Services and Tourism Commerce of Mexico City said this week that anti-pollution driving restrictions since April had cost more than $300 million to city residents, small shops and service providers whose transportation was curtailed.