In India's capital, New Delhi, air pollution levels are soaring.
Since November began, experts say the amount of particulate matter in the air has been up to ten times higher than normal.
Ankita Bansal, a New Delhi resident, said: "It's worsening. I mean we feel breathlessness towards the end of the day."
Those with respiratory problems are in worse shape.
Dr. Vivek Nangia, the Director of Pulmonology at Fortis Hospital says his caseload has risen about 30-percent during the past week.
"And I would attribute it to pollution levels only, because till about a week or ten days back, this number was not so high."
Smog levels are always high in Delhi during November and December, because of falling temperatures and the seasonal burning of paddy fields.
But officials say emissions from the increasing number of diesel vehicles in the city are making this year even worse.
Experts say about a third of the pollution comes from the 52,000 vehicles that enter the land-locked city each day.
As the temperatures continue to fall, they warn that the pollution could get even worse.