The air quality is bad primarily due to several key factors:

• The burning of fossil fuels such as coal, oil, and gasoline produces pollutants including carbon monoxide, nitrogen oxides, and particulate matter that harm respiratory and heart health. This is a major source of outdoor air pollution.

• Indoor air pollution can also be severe, caused by volatile organic compounds (VOCs), smoke, mold, and inadequate ventilation inside buildings.

• Wildfires and burning of biomass release large amounts of fine particulate matter (PM2.5) and create smog which makes it difficult to breathe.

• Ground-level ozone forms when sunlight reacts with chemicals from burning fossil fuels. Ozone is a harmful pollutant contributing to smog.

• Other harmful pollutants include sulfur dioxide , nitrogen dioxide, and particulate matter which are often linked to industrial activities and vehicle emissions.

• Climate change worsens air quality by increasing wildfires, heatwaves, and ozone formation.

Overall, the combination of fossil fuel combustion, industrial emissions, wildfires, indoor pollutants, and climate factors leads to poor air quality, which in turn causes respiratory issues, heart problems, and premature deaths worldwide.