But the slowdown also has cut air pollution by more than a third in Cairo, a city once ranked as one of the world's 10 dirtiest.

According to data released by the Ministry of Environment, air quality has improved in Greater Cairo by 36% and in coastal cities and the Nile Delta by more than 40% since the lockdown and curfew went into effect.

Bassant Fahmi, an economist and a parliamentarian, said that turning to clean mass transit and encouraging more cycling would not only reduce traffic and air pollution but also boost the economy, which loses billions of dollars each year to traffic congestion and air-pollution-related health problems.

About 90% of Egyptians breathe air dirty air, most of them in Greater Cairo and other cities, the ministry said.

Fahmi suggested that reviving legislation from the 1970s that obliged owners of shops, workshops and commercial centers to close early to limit traffic and pollution could also help preserve air quality gains made during the pandemic lockdown.