The presence of substances and gases which are harmful to the living organisms in the air is called air pollution.
Three human activities that causes air pollution are :-
1. use of different types of vehicles like cars,buses,bikes,autos will lead to the release harmful gases like carbon monoxide, carbon dioxide etc...
2. by burning fossil fuels and plastic in open air will lead to the release of harmful gases into the air.
3. different industries and factories release different types of toxic chemicals into to the air will also lead to the release of harmful gases into the air.
two harmful effects of air pollution are :-
1. people will suffer from different types of uncurable diseases.
2. ozone layer will be slowly depleted.