A panel of experts in the Indian capital on Friday declared a health emergency because of pollution affecting the city, so the authorities ordered suspension of classes until November 5.

The Supreme Court panel also temporarily banned construction activities in the New Delhi metropolitan area to control the amount of dust and pollutants in the air.

Pollution in the city generally increases around early November, due to a combination of smoke from fireworks thrown during a Hindu festival and that resulting from the burning of fields in neighboring states.

The air quality index read at the U.S. Embassy in New Delhi for particulate pollutants on Friday reached a level nine times higher than that recommended by WHO. At these levels it is recommended to avoid outdoor activity due to health risks.

India’s chief elected official, Arvind Kejriwal, announced a plan to restrict the movement of private cars in New Delhi for nearly two weeks, starting Monday.

Private cars that use gasoline or diesel will be able to circulate in the city only on alternate days from 4 to 15 November, depending on whether their license plates end in even numbers or not.

Kejriwal said similar restrictions applied in 2016 reduced pollution by as much as 13%.

On Friday, he distributed masks free of charge to groups of children.

Last month, the official announced plans to mechanically sweep roads, plant trees and control air pollution at 12 hot spots in the city.

India has some of the world’s most polluted cities.