Last week, Paris was more polluted than New Delhi and Beijing. On Friday, PM10 levels in the Paris region exceeded 100 micrograms per cubic meter. The city had world’s dirtiest air, according to Plume Labs, which monitors air quality in dozens of cities worldwide. This is putting health in danger The smog blocked out the view of the Eiffel Tower. As a measure to stimulate alternative traffic, free rides on public transport were introduced on Saturday and Monday. Everyone will get a one day subscription to the city’s bike-sharing program.