Question

why was caliform bacteria chosen to indicate the level of pollution in ganga mention 2 major factors

Answer 1

Coliform bacteria are indicators of feacal contamination of water since they thrive best in the feaces of warm blooded organisms. They also indicate the possible presence of pathogenic (disease-causing) bacteria, viruses, and protozoans that also live in human and animal digestive systems.

Aside from these, they are very easily isolated, cultured and identified in an adequate number than any other pathogenic bacteria, thus they have been used for water quality testings since the past centuries.