The falling air quality is taking a toll on the health of lakhs of asthmatics and people with impaired lung function. Exposure to air in heavy traffic triggers severe wheezing immediately, and emergency hospital visits have shot up over the years. BharatiChaturvedi, an environmentalist who has had asthma most of her life, stays in her bedroom on severe smog days. "I have stopped walking my dog on such days. I can't. Both 2013 and 2014 were terrible for me."

Bharati says her asthma complications were seasonal in childhood but now they can happen any time. She has installed an air purifier in her bedroom. "I am on steroid medicines and inhaler most of the time but I refuse to leave the city. The government's bad policies shouldn't throw me out of my house, right?"

Bharati is a birder and her asthma subsides when she is out birding in rural Haryana. She wants the government to treat air pollution as a state emergency and take private diesel vehicles off the roads.

Rahul Goel, who works at a coffee shop in Connaught Place, cannot ride his bike without using a handkerchief as a mask. "If I spend even a few minutes in traffic with my nose and mouth exposed, I need an inhaler. I feel like I will collapse, the wheezing is so bad." Goel, who has bronchial asthma, had an attack two years ago after he came back from Kerala. He said he never had such complications when he was studying in Calicut. "I want to move to Uttarakhand or Himachal Pradesh for a better life. In the past six years my life has become difficult, I don't want to tie a handkerchief around my face every day."

Kiran Devi, who is being treated at Vallabhbhai Patel Chest Institute, also avoids stepping out of her house. She has two children to take care of and worries about having an emergency. "I am much better when I am at my uncle's village in Haryana. But I don't get to go there often," she said.

Suhasini Mukherjee's asthma attacks have become frequent ever since she came to intern in Delhi from Pune. "It gets worse after March and Diwali is horrible for her. She wheezes heavily amid exhaust smoke," said Chitra Mukherjee, her mother.

AmeetaMullaWattal, principal of Springdales School, Pusa Road said a lot of students call in sick on smog days and around Diwali. "They carry puffs and their physical activity is reduced dramatically during those days. We conduct a health study of students every year and have been seeing a rise in asthma, diabetes and psychosomatic diseases."

Pollution does not cause asthma but it worsens it. DrVikramJaggi, director of Asthma Chest and Allergy Centre says asthma is common in Australia and New Zealand although the air is clean. "Air pollution affects lung health and function in general. In an extremely polluted city, the effect is similar to breathing six to seven cigarettes. It affects children and the elderly the most because their airways are smaller and weaker."

Allergies and air pollution are linked, said Dr S K Chhabra, head of cardio-respiratory physiology at Vallabhbhai Patel Chest Institute. It aggravates allergies and is linked to chronic bronchitis and heart failure. Doctors also said some of air pollution's effects on health are invisible.