Public transport will be temporarily free in Geneva for the first time in Switzerland as part of a series of measures aimed at tackling rising air pollution in the city.

Geneva, in the western French-speaking part of Switzerland, is experiencing a severe peak in ozone pollution – a harmful gas that can cause breathing problems, headaches and asthma attacks, according to the World Health Organization.

According to measurements, ozone concentrations in the city exceeded the health safety limit of 180 micrograms per cubic meter over a 24-hour period, according to a statement from the canton of Geneva.

Yesterday, Tuesday, temperatures reached 37 degrees Celsius with the government issuing heatwave warnings for western and southern parts of Switzerland.

The high temperatures and low cloud cover mean ozone pollutants are building up and taking longer to dissipate, the canton of Geneva’s environment office told Reuters.

In response, public transport was made free for the first time today across the canton to encourage residents and visitors to switch from their cars to buses, trams, trains and boats to reduce pollutant emissions from traffic.

“The measures taken under this emergency protocol are aimed at reducing nitrous oxide emissions, mainly by promoting public transport and limiting the circulation of the most polluting vehicles,” the environment bureau said.

Passengers will not need a ticket and ticket inspections will be suspended until the pollution situation improves, authorities said in a statement.

Between 6 a.m. and 10 p.m. only lower-emission cars will be allowed in the city center.