I have been following global air pollution reports and I am shocked by how bad the air quality is in some cities. It seems that every year, lists of the most polluted cities get longer and more alarming. I am curious which cities currently have the worst air quality and what factors contribute to it. Is it mostly vehicle emissions, industrial activity, or perhaps geographical factors that trap pollutants? 
I also want to understand the health implications for residents and what precautions they take. Are masks, air purifiers, or staying indoors enough, or is the problem too severe? If anyone has lived in or visited these cities, I would love to hear firsthand experiences and advice on coping with extremely polluted air.
Cities like Delhi, Lahore, and Beijing are often reported as having the worst air quality. Vehicle emissions, industrial output, and burning of crop residue in surrounding areas contribute heavily. During winter months, smog tends to worsen due to low temperatures and stagnant air. Residents often wear masks, avoid outdoor exercise, and use air purifiers indoors to protect themselves. I visited Delhi once and the haze was visible across the skyline. It felt like breathing through a filter.
I lived in Lahore for a few months and noticed how bad air quality affects daily life. Even short walks outside can cause irritation in the eyes and throat. Children and elderly people are particularly vulnerable. Many people use portable AQI monitors to plan outdoor activities, and masks are worn almost daily. It is frightening to see how pervasive pollution is in some urban areas.
Thank you, I will start checking AQI before going out!
Beijing experiences extremely high pollution especially in winter. Government policies like restricting vehicle use and implementing emissions standards help slightly, but during peak smog days, the air quality is still hazardous. People often limit outdoor activities and use air purifiers indoors. I noticed that daily life routines are adapted around pollution levels, which is sad but necessary.
Some cities in Pakistan and India experience air quality levels far beyond safe limits. PM2.5 and PM10 concentrations can reach dangerous levels, affecting respiratory health and increasing hospital visits. Many locals carry masks and avoid peak traffic areas. It is not just a health issue but also a quality of life problem. 
Industrial cities in China like Shijiazhuang and Linfen also have very poor air quality. Heavy coal usage, factories, and vehicle emissions combine to create a thick smog. Residents have to be careful about outdoor exposure and rely heavily on air purifiers at home. It is remarkable how quickly people adapt to living with polluted air.