What is pH level, what are its characteristics, and how does it contribute to pollution?

pH Scale:

The pH scale refers to the negative logarithm of molar concentration of hydrogen ions: pH = - log [H+].

Characteristics:

The pH scale ranges from 0 to 14. A solution of a compound of pH 7 or pOH 7 is a neutral solution. Solutions of pH less than 7 are acidic and more than 7 are basic.

Low pH of water is acidic in nature as it enters into the ground and collects in streams, it can have bad impacts on the ecosystem.