pH of drinking water should be between 5.5 $$-$$ 9.5

Concentration of DO below 6 ppm is good for the growth of fish.

Clean water would have a BOD value of less than 5 ppm.

Oxides of sulphur, nitrogen and carbon are the most widespread air pollutant.

are related to the depletion of ozone layer

study the reactions in plants

produce colour during reactions

reduce the use and production of hazardous chemicals.