Final answer:
The correct answer is Beijing. Beijing has faced significant air pollution issues, especially during the hosting of the Summer Olympics in 2008. Poor air quality and smog have caused health concerns and grounded aircraft.
Step-by-step explanation:
Air pollution, caused by the release of harmful substances into the atmosphere, poses a grave threat to human health and the environment. It includes pollutants such as particulate matter and gases, contributing to respiratory diseases, climate change, and ecological damage.
In recent years, Beijing, China has faced significant air pollution issues, especially during the hosting of the Summer Olympics in 2008. China's fast-growing economy and burgeoning industry have led to poor air quality, with smog hanging heavily over the major cities. This has caused health concerns for citizens and has even grounded aircraft. The government has implemented measures to address the issue, but there is still skepticism among the public about the accuracy of pollution measurements.