“When I stepped out of my house, it felt like I was inhaling smoke,” says Imran Ahmed Ali, a lawyer in the northern Indian city of Chandigarh.

Pollution levels in Chandigarh – India’s first planned city, located about 240km (150 miles) from capital Delhi – have been at more than 15 times the safe limit recommended by the World Health Organization (WHO) for more than a month.

It is now common for air quality in the city to dip every winter, but Mr Ali says he has never felt so sick before.

A few weeks ago, the 31-year-old began experiencing a dry cough and shortness of breath, which he initially dismissed as symptoms of a seasonal cold. But as the temperature dropped, his chest congestion worsened and he went to a doctor.

“After running several tests, the doctor told me that my symptoms were caused by pollution. I’m now taking medicine twice a day to manage my breathing,” he says.

Mr Ali is among hundreds of millions of people living in northern India who are forced to breathe toxic polluted air for extended periods every winter.

According to Swiss firm IQAir, eight of the 10 most polluted cities in the world last year were located in the Indo-Gangetic plains – a densely populated region which stretches across northern and eastern India, along with parts of Pakistan and Nepal.

A recent report by the Energy Policy Institute at the University of Chicago reiterates that the northern plains – home to 540.7 million people across Bihar, Chandigarh, Delhi, Haryana, Punjab, Uttar Pradesh, and West Bengal – is the most polluted region in India. When compared with the WHO’s standards, air pollution at current levels could reduce the life expectancy of people here by 5.4 years, it adds.

But as the toxic smog closes in every winter, headlines and attention are mostly focused on Delhi.

Continue reading at the BBC…