81.
Which one of the following metals pollutes the air of a city having large number of automobiles?

82.
Pollutant from motor car exhaust that causes mental disease is

83.
The most common cause of pollution of air is

84.
Particulates (< 1 µm size) remaining suspended in air indefinitely and transported by wind currents are called

85.
Mercury is emitted into air by

86.
'Acid rain' is caused due to air pollution by

87.
Gas released during Bhopal tragedy was :

88.
The filter over which sewage is sprinkled is called as

89.
Main source of lead pollution is from

90.
An example of major air pollutant is