On Bad Air Days in India, Staying Inside Doesn't Help NEW DELHI - Air pollution in this massive city is about twice as bad as it is in Beijing, infamous the world over for its bad air. But Indians" poor lung function results from more than just outdoor air pollution. Indians are exposed to high levels of toxic bacteria because more than half of the country's vast population defecates outside. The ensuing infections stunt growth, reducing lung sizes. And indoor air quality in India is often poor because many rural households cook with dried dung. A worsening dengue epidemic has also led many to burn mosquito coils, whose nightly smoke in a home can exceed that from 100 cigarettes, according to Dr. Sundeep Salvi, director of the Chest Research Foundation in Pune. These factors, along with outdoor air pollution, may help explain why Indians have among the weakest lungs in the world - with a recent study finding that Indians" lung capacities are an astonishing 38 percent lower than those of North Americans and far lower than those of Chinese. A 2012 study of 11,628 Delhi schoolchildren found that a third had reduced lung function and that the studied children had four times more iron-laden white blood cells in their sputum than children from less polluted locales. "And I think India's problems are going to get a lot worse," Dr. Salvi said. Delhi's air pollution tends to peak around midnight. The city bans large trucks from its roads during the day, but they are allowed through at night. The city's ring road has long since been swallowed by development so the trucks cut through the center of the city. J.S. Kamyotra, a member secretary of Delhi's Central Pollution Control Board, said that the construction of the city's metro rail system should help. "All efforts are being made," he said. Dr. Anurag Agrawal, a pulmonary physician and researcher based in New Delhi, decided with his wife in 2003 to move back to India from the United States because they wanted to be near family and thought the air was getting better. He has asthma, as does his 11-year-old daughter, and both his father and grandfather died of asthma. "But now, when smog makes it difficult to breathe, we think that we may be making a mistake that could seriously affect our health," Dr. Agrawal said. Whether we should move out of Delhi, we don't know. At the All India Institute of Medical Sciences in New Delhi, scores of children and their parents were waiting on a recent day to receive breathing treatments and get seen by doctors. A 2-year-old wearing a Kung Fu Panda sweatshirt and sitting on his mother's lap grasped an inhaler with practiced ease and breathed in the life-giving medicine, sighing deeply when done. A 3-year-old girl was next and then a 10-month-old boy in an unending stream of suffering, with each patient getting about five minutes with Dr. S.K. Kabra before the next child was hustled in. A resident brought lung X-rays of one child and put them on a light panel to show them to Dr. Kabra, but the panel was broken. Dr. Kabra held them up to the overhead light himself. The child had been diagnosed by a quack as suffering from tuberculosis and had been taking antibiotics for months with no effect. Dr. Kabra shook his head. The child had asthma, not tuberculosis. Kitty Chachra moved back to India from the San Francisco Bay Area in 2004 with her husband and two children. Her 14-year-old son's asthma gets worse every year and is now a constant source of worry for her, she said. She believes that a decade of steroid use to treat his breathing woes has left him shorter than he might have been, a known side effect. On summer vacations in North America, her son does not need asthma medications but restarts them upon returning to Delhi. "I think he would have just grown out of this if we'd stayed in the U.S.," Ms. Chachra said. I'm very disillusioned. Gardiner Harris's story on air pollution in New Delhi describes how residents of Beijing appear to be more concerned about the air quality in their country than the residents of India's capital. Why do you think Delhi's air pollution has received so much less attention than the pollution in Beijing? Please leave your thoughts in the comments section.