Zagreb was one of the world's ten cities with the highest air pollution on Friday, according to the Swiss IQAir website that publishes global data on air quality, the Jutarnji List daily issue of Saturday reports.

At 8 am on Friday, Zagreb was among the world’s three cities with the highest air pollution, together with Lahore, Pakistan, and Delhi, India, but it dropped to sixth place during the day.

The air quality index at 8 am on Friday in the Croatian capital was 169 and at noon it was 153, which is considered poor quality air for sensitive population groups.

The Economy and Sustainable Development Ministry said the increased levels of air pollution at this time of the year have to do with fog and lack of wind and the start of the heating season, as well as with a phenomenon called thermal inversion, with air temperature increasing with height.

The “Andrija Štampar” Public Health Institute has recommended sensitive population groups, notably children, pregnant women, the elderly and people suffering from chronic respiratory or cardiovascular diseases avoid long and intensive outdoor activity, especially near thoroughfares.