Northern India is enveloped in smog in the month of November because of the following causes:
- Crop Residue Burning — In Punjab and Haryana, farmers often burn crop residues after harvesting to prepare the fields for the next crop. This releases a significant amount of smoke and particulate matter into the air.
- Stubble Burning — The burning of leftover crop residue in the fields is a common practice after rice harvesting and contributes to the smog problem in northern India.
- Diwali Celebrations — Diwali is celebrated with fireworks and firecrackers, which releases a large amount of pollutants, including particulate matter and toxic chemicals into the atmosphere.
- Industrial Emissions — The industrial activities and factories in the region release pollutants like sulphur dioxide, nitrogen dioxide and particulate matter into the air, contributing to the smog formation.
- Vehicular Emissions — The high number of vehicles in the region contribute to air pollution through exhaust emissions.