India has declared a health emergency after toxic smog in New Delhi.
Local hospitals have seen a sharp increase in respiratory and cardiac complaints.
Schools are closed until November 5th and residents are encouraged to stay inside.
Air quality levels are over 400, nine times the level recommended by the World Health Organization.
The atmospheric pollutants or gases that form smog are released in the air when fuels are burnt. When sunlight and its heat react with these gases and fine particles in the atmosphere, smog is formed. It is purely caused by air pollution.