It is caused by both Natural and Manmade factors
Natural Factors
Due to forest fires and volcanoes, smoke and dust rise in atmosphere
Man Made Factors
It is also caused by activities of human beings like
- Smoke from Factories
- Burning of Fuel (Cow dung cake and wood) cause pollution
- Automobiles exhaust smoke from Vehicles which release harmful chemicals and gases like carbon monoxide, carbon dioxide, nitrogen oxides and smoke