According to the WHO, indoor air pollution is one of the biggest preventable health risks worldwide. It mainly occurs when cooking and heating with solid fuels such as wood, coal, or kerosene in poorly ventilated indoor spaces. This releases dangerous pollutants such as fine particulate matter (PM2.5), which cause heart and lung disease, respiratory infections, and millions of premature deaths.

In January 2026, Sarajevo ranked among the world’s most polluted cities, with air quality levels exceeding WHO safety limits. New research reveals why this winter smog keeps returning and what could finally change it.

Delhi is one of the world’s most polluted cities in part due to problematic waste-to-energy plants like the one in Okhla. Investigations reveal the release of toxic heavy metals such as cadmium and lead. This poses a serious risk to indoor air quality, especially in buildings with poor ventilation or filtration. This article explores how building technology and clean air strategies can help protect occupants from hidden pollution.