Compressed Natural Gas $(CNG)$ is primarily composed of:

Drinking of mineral water with a very low level of pesticides (about $0.02 \text{ ppm}$) for long periods may:

Biochemical Oxygen Demand $(BOD)$ is not a good index for pollution in water bodies receiving effluents from which of the following?

What is the $BOD$ limit prescribed by the $CPCB$ for natural water bodies into which municipal waste is discharged?

Name the states involved in the Ganga Action Plan.

In the treatment of wastewater,scientists at the Arcata Marsh (a project associated with Humboldt State University) developed a series of six connected marshes over how much area to remove heavy metals and other pollutants?