The major cause $(80\%)$ of air pollution in big cities is due to

Electrostatic precipitator : remove particulate matter :: scrubbers : ..........

In cities like Mumbai and Kolkata,the major air pollutants are .....

Generally speaking,the atmosphere in big cities is polluted most by

According to the Central Pollution Control Board $(CPCB)$,which particulate size in diameter (in micrometers) of air pollutants is responsible for the greatest harm to human health?

Most hazardous metal pollutant of automobile exhaust is